llSIIiiiillillllif 


ft** 


LIBRARY 

OF  THE 

UNIVERSITY  OF  CALIFORNIA. 

01  FT  OF 


Class 


THE 


NATURAL  LAWS  OF  HUSBANDRY. 


BY 

JUSTUS  VON  LIEBIG. 


EDITED   BY 

JOHN  BLYTH,  M.D., 

PROFESSOR   OP    CHEMISTRY    IN    QUEEN'S    COLLEGE,    CORK. 


NEW  YORK : 
D.   APPLETON    AND    COMPANY, 

443  &  445  BEOADWAY. 

1863. 


EDITOE'S  PEEFACE. 


IN  the  following  work  Baron  Liebig  has  given  to  the 
public  his  mature  views  on  agriculture,  after  sixteen 
years  of  experiments  and  reflection.  The  fundamental 
basis  of  the  work  is  still  the  so-called  Mineral  Theory, 
which  holds  that  the  food  of  plants  is  of  inorganic  nature, 
and  that  every  one  of  the  elements  of  food  must  be  present 
in  a  soil  for  the  proper  growth  of  a  plant.  The  discovery 
of  the  remarkable  power  of  absorption  possessed  by  arable 
soils  has  necessarily  led  to  a  modification  of  the  views  re- 
garding the  mode  in  which  plants  take  up  their  food  from 
the  soil.  As  the  food  of  plants  cannot  exist  for  any  length 
of  time  in  solution  in  soils,  it  is  clear  that  there  cannot  be 
a  circulation  of  such  solution  towards  the  roots,  but  the 
latter  must  go  in  search  of  food.  Hence  the  great  impor- 
tance of  studying  the  ramification  of  the  roots  of  plants,  and 
the  mode  of  growth  of  the  different  classes  of  plants  culti- 
vated by  man.  The  first  chapter  is  devoted  to  the  consid- 
eretion  of  the  growth  of  plants,  of  the  formation  of  their 
roots,  and  of  their  power  of  selecting  food,  and  the  part 
played  by  the  mineral  matters  which  are  absorbed. 

If  the  food  of  plants  is  not  in  solution  in  the  ground, 
we  can  conceive  that  those  portions  of  the  soil  traversed  by 
the  numerous  root  ramifications  will  be  more  or  less  ex- 
hausted of  food  elements,  whilst  the  immediate  neighbour- 


All 


ing  portions  are  still  rich  in  them.  If,  therefore,  a  suc- 
ceeding crop  is  to  grow  equally  well  on  all  parts  of  a  field, 
there  must  be  a  thorough  mixing  of  the  exhausted  and  of 
the  unexhausted  portions  of  soil.  This  is  effected  by  mechan- 
ical means,  by  manures,  or  by  certain  chemical  compounds. 
Hence  the  necessity  of  becoming  acquainted  with  the  na- 
ture and  properties  of  the  soil  and  subsoil.  The  second 
chapter  is  devoted  to  this  subject. 

The  soil  consists  of  arable  surface  soil  and  subsoil.  In 
the  former  is  accumulated  the  nutriment  of  plants  chiefly 
cultivated  for  the  food  of  man.  This*  accumulation  is 
affected  by  the  absorptive  power  of  the  arable  soil  for 
mineral  matters,  by  which  soluble  salts  are  removed  from 
solution,  and  even  chemical  decomposition  of  the  most 
stable  compounds  is  brought  about,  and  the  bases  or  acids 
are  retained  by  the  soil  in  a  firm  state  of  combination.  It 
is  the  presence  of  food  in  the  soil  in  this  state  of  phys- 
ical combination  which  is  alone  available  for  the  nutrition 
of  plants.  On  the  abundant  or  scanty  supply  of  food  in 
this  state  depends  the  fertility  or  sterility  of  a  soil.  In 
fertile  soils  food  is  present  also  in  another  form,  in  whicli 
it  is  not  immediately  available  for  the  nutrition  of  plants. 
It  exists  as  chemical  compounds  which  are  not  soluble  in 
water,  or  acids  until  rendered  so  by  the  action  of  power- 
ful chemical  agents,  or  to  a  much  smaller  extent  by  the 
slower  process  of  the  decomposing  action  of  the  weather. 
When  the  food  is  eliminated  by  disintegration  (by  fallow 
and  mechanical  operations)  from  this  inert  state  of  chem- 
ical combination,  it  passes  into  that  of  physical  combination 
with  the  earthy  particles  before  it  is  absorbed  by  the 
plant.  Each  kind  of  soil  has  its  own  absorptive  power  for 
causing  the  food  to  pass  into  a  state  of  physical  combina- 
tion. When  manure  is  applied,  its  greater  or  less  disper- 
sion throughout  the  soil  will  depend  on  this  power.  In 
general  it  is  absorbed  and  fixed  by  the  upper  few  inches 


of  the  soil,  a  smaller  quantity  penetrates  to  the  lower  lay- 
ers, and  scarcely  any  at  all  to  the  deep  layers  and  subsoil. 
Hence  when  a  subsoil  is  exhausted,  manure  cannot  restore 
its  fertility.  From  this  peculiar  property  of  soils  of  ar- 
resting the  circulation  of  solutions  of  the  food  of  plants, 
arises  the  necessity  of  employing  means  for  the  distribu- 
tion of  food,  and  for  the  uniform  mixture  of  the  different 
layers  of  the  soil.  The  manner  in  which  this  is  effected  by 
mechanical  operations,  by  organic  matter,  by  manures,  by 
certain  chemical  salts,  &o.,  is  pointed  out  in  chapters  sec- 
ond, third,  and  twelfth. 

The  quantity  of  food  in  a  state  of  physical  combination 
in  any  fertile  soil  is  only  limited.  Continuous  cultivation 
without  replacement  of  all  the  mineral  matters  removed 
hi  the  crops  destroys  fertility,  either  by  causing  the  abso- 
lute loss  of  the  assimilable  food,  or  by  altering  the  proper 
relative  proportions  between  the  different  elements  of  food, 
to  such  an  extent  that  the  due  growth  of  all  parts  of  the 
plant  is  altered.  For  the  successful  growth  of  a  plant  in 
all  its  parts,  every  element  of  food  is  required.  Not  one 
substance  has  any  superior  fertilising  power  over  another. 
The  average  crop  of  an  unmanured  field  is  always  regu^ 
lated  by  that  element  of  food  which  is  present  in  minimum 
quantity.  The  effect  of  a  manure  when  beneficial  is  merely 
to  increase  the  relative  proportion  of  this  minimum  ele- 
ment. If  the  minimum  matter  was  known  in  each  case, 
its  direct  application  would  be  sufficient  to  increase  the 
fertility  of  the  soil.  But  as  in  general  this  point  is  not 
ascertained,  the  application  of  farm-yard  manure  is  certain 
in  producing  a  fertilising  effect,  simply  because  it  is  a  com- 
plex mixture  containing  all  the  food  elements  of  plants, 
and  consequently  whilst  supplying  other  matters  which 
are  not  immediately  wanted,  it  also  furnishes  the  minimum 
substance.  In  chapter  fourth,  is  discussed  the  question  of 
this  altered  composition  of  the  ground  by  cultivation. 


6 

In  chapter  eleventh,  the  fact  that  not  one  of  the  ele- 
ments of  food  by  itself  possesses  any  superior  nutritive 
value  over  the  others  is  further  discussed.  Nitrogenous 
food,  like  all  the  rest,  must  be  present  if  a  plant  is  to  grow 
properly,  but  no  excess  of  this  element  of  food  will  of 
itself  produce  more  abundant  crops.  The  analyses  of  soils 
show  that  they  abound  in  nitrogen.  Were  all  other  sources 
of  this  element  wanting,  there  would  still  be  a  continued 
supply  provided  for  hi  rain  and  dew,  and  in  the  many  pro- 
cesses of  oxidation  going  on  at  the  surface  of  the  earth. 
Probably,  wherever  we  have  a  generation  and  circulation 
of  carbonic  acid,  there  is  also  a  provision  for  the  forma- 
tion of  nitrogenous  compounds.  When  Nature  thus  pro- 
vides for  a  supply  of  nitrogen  without  the  aid  of  man,  it  is 
likely  that  exhaustion  of  all  other  elements  of  food  in  the 
soil  will  take  place  by  cultivation  before  this  occurs  with 
nitrogen.  The  inefficacy  of  the  mass  of  nitrogen  in  the 
soil  cannot  be  attributed  to  its  existing  in  two  forms,  hi 
one  only  of  which  it  is  assimilable.  This  is  proved  by  ex- 
periments with  soils  and  with  farm-yard  manure.  When 
the  nitrogen  of  the  soil  is  not  available,  some  other  cause 
must  be  sought  for  than  its  existence  in  a  state  in  which  it 
is  sparingly  assimilable.  This  cause  will  be  found  to  be 
the  absence  of  some  other  elements  of  food,  which,  upon 
being  supplied,  will  at  once  render  the  seemingly  inopera- 
tive nitrogen  at  once  energetic. 

The  diminution  of  the  amount  of  available  food  ele- 
ments in  the  arable  surface  soil,  by  the  cultivation  and  sale 
of  corn,  necessitates  the  restoration  of  the  removed  mineral 
matters.  This  is  effected  to  a  limited  extent  by  foreign 
manuring  agents,  but  chiefly  by  the  formation  of  manure 
by  means  of  fodder  plants.  By  the  system  of  rotation, 
green  crops  which  draw  their  nutriment  from  the  subsoil 
are  introduced  between  the  cereals.  By  the  deep  pene- 
trating roots  of  the  former,  the  mineral  matters  of  the 


EDITOR'S  PREFACE. 


subsoil  are  absorbed,  and  in  the  form  of  manure  are  trans- 
ferred to  the  arable  surface  soil.  But  if  this  process  con- 
tinues, and  the  corn  and  cattle  are  still  sold,  and  no  re- 
placement from  without  is  made  of  the  lost  mineral  matters, 
the  time  will  arrive,  sooner  or  later,  when  the  subsoil  be- 
comes exhausted,  and  the  surface  soil  having  no  longer  a 
reservoir  from  which  to  draw  supplies  by  means  of  fodder 
plants,  is  also  unable  to  bear  remunerative  crops.  This 
natural  progress  of  the  system  of  farm-yard  manuring  is 
fully  discussed  in  chapter  fifth.  The  reader  must  not  sup- 
pose that  the  condemnation  passed  on  the  system  of  farm- 
yard manuring  is  meant  to  apply  to  farm-yard  manure  itself. 
The  latter  is  the  type  of  a  valuable  manure  which  cannot 
be  replaced  in  every  respect  by  any  artificial  mixtures  in 
use.  The  remarks  of  the  author  only  apply  to  the  falla- 
cious hopes  entertained  of  keeping  up  permanently  the 
fertility  of  the  soil  by  manure  obtained  by  the  system  of 
rotation,  whilst  we  continue  still  to  sell  the  corn  raised  by 
such  manure  without  bringing  back  to  the  soil  any  portion 
of  the  mineral  matter  sold  with  the  corn  and  cattle. 

The  excrements  of  man  contain  all  the  mineral  matter 
not  only  of  the  corn,  but  also  of  the  cattle  sold  from  the 
land.  Could  we  restore  these  excrements  to  the  soil,  a  per- 
fect circulation  of  the  conditions  of  life  for  plants  and  ani- 
mals would  be  established,  and  our  fields  would  be  retained 
in  a  permanent  state  of  fertility.  This  problem  has  been 
solved  by  the  Chinese  and  Japanese.  Chinese  rural  life,  as 
it  is  described  by  travellers,  as  well  as  the  report  of  the 
Japanese  system  of  husbandry  given  in  Appendix  G.  by 
Dr.  Maron,  would  scarcely  lead  us  to  wish  for  the  improve- 
ment of  agriculture  upon  the  plan  of  these  Orientals  !  The 
requirements  of  modern  civilization  would  not  permit  the 
purchase  of  manuring  matter,  however  valuable,  at  the  cost 
of  all  domestic  comfort.  The  sewers  must,  we  fear,  still 
receive  what  would  be  offensive  to  our  English  senses. 


8  EDITOR'S  PEEFACE. 

But  can  the  contents  of  these  sewers  not  be  made  avail- 
able ?  The  great  mass  of  water  which  necessarily  accom- 
panies at  present  the  fertilising  matters,  renders  them  of 
comparatively  little  value  when  compared  with  the  expense 
of  transport.  But  how  to  separate  and  concentrate  these 
matters  from  the  water  is  a  problem  which  is  at  present 
occupying  the  earnest  attention  of  scientific  and  practical 
men.  The  solutions  hitherto  proposed  are  far  from  satis- 
factory. The  future  of  agriculture  is,  however,  ultimately 
connected  with  the  right  solution  of  this  great  sewage 
question. 

In  conclusion,  I  have  only  to  state  that  the  foreign 
weights  and  measures  have  been,  when  necessary,  trans- 
lated into  their  equivalents  in  English,  but  have  been  left 
unaltered  when  the  point  was  only  one  of  comparison, 
which  could  be  equally  illustrated  by  the  foreign  weights. 

J.  BLYTH,  M.  D. 

QUEEN'S  COLLEGE,  CORK  : 
March  16,  1863. 


PEEFAOE. 


IN  the  sixteen  years  which  have  intervened  between  this 
work  and  the  sixth  edition  of  my  '  Chemistry  applied 
to  Agriculture  and  Physiology,'  I  have  had  sufficient  op- 
portunity to  become  acquainted  with  all  the  obstacles 
which  are  opposed  to  the  introduction  of  scientific  teach- 
ing into  the  domain  of  practical  agriculture.  Among 
the  chief  of  these  may  be  reckoned  the  complete  sep- 
aration which  has  always  existed  between  science  and 
practice. 

There  has  generally  prevailed  an  idea  that  a  smaller 
amount  of  information  and  intelligence  is  required  for  agri- 
cultural pursuits  than  for  any  other  occupation ;  nay,  that  the 
practical  skill  of  the  farmer  is  only  likely  to  be  injured 
when  he  has  recourse  to  science.  *  Whatever  requires 
thought  and  reflection  is  regarded  as  theory,  which  being 
the  opposite  of  practice,  must,  of  course,  be  of  little  value. 
The  natural  result  of  such  opinions  is,  that  when  the  prac- 
tical man  does  attempt  to  apply  scientific  teaching,  he  is 
almost  invariably  a  sufferer.  He  seems  altogether  to  for- 
get that  man  does  not  become  intuitively  acquainted  with 
scientific  teaching,  which,  like  the  skilful  use  of  any  com- 
plex instrument,  must  be  learned. 

The  truth  or  error  of  the  notions  which  guide  our  prac- 
l* 


10  PREFACE. 

tice  cannot,  however,  be  regarded  as  a  matter  of  indiffer- 
ence. 

The  more  correct  ideas  which  science  has  given  us  of 
the  growth  of  plants,  and  the  part  played  in  the  process  by 
the  soil,  air,  mechanical  operations,  and  manure,  is  not  re- 
garded in  the  light  of  an  improvement  by  the  practical 
man,  simply  because  his  ignorance  does  not  enable  him  to 
appreciate  the  information.  Unable  to  find  out  the  con- 
nection between  scientific  teaching  and  the  phenomena  pre- 
sented in  his  daily  pursuit,  he  naturally  comes  to  the  con- 
clusion, from  his  point  of  view,  that  there  really  exists  no 
connection  between  them. 

The  practical  agriculturist  is  guided  by  facts  observed 
in  his  own  neighbourhood  for  a  long  period ;  or,  if  his  views 
are  more  comprehensive,  he  follows  certain  authorities 
whose  system  of  husbandry  is  held  to  be  the  best.  It  never 
enters  into  his  thoughts  to  submit  this  system  to  proof,  for 
he  has  no  standard  of  comparison  at  hand.  What  Thaer  dis- 
covered to  be  useful  in  Moglin  was  held  to  be  equally  so 
for  all  Germany,  and  the  facts  which  Lawes  found  to  be 
true  on  a  very  small  piece  of  land  at  Rothamsted  have  be- 
come axioms  for  all  England. 

Under  the  dominion  of  tradition  and  of  slavish  submis- 
sion to  authority,  the  practical  man  has  lost  the  faculty  of 
forming  a  right  conception  of  the  facts  which  daily  pass 
before  his  eyes,  and  in  the  end  can  no  longer  distinguish 
facts  from  opinions.  Hence,  when  science  rejects  his  ex- 
planations of  any  particular  facts,  it  is  asserted  that  the 
facts  are  themselves  denied.  If  science  declares  that  we 
have  made  progress  in  substituting  for  deficient  farm-yard 
manure  its  active  ingredients,  or  that  superphosphate  of 
lime  is  no  special  manure  for  turnips  nor  ammonia  for 
corn,  it  is  imagined  that  the  utility  of  these  substances  is 
contested. 

Long  disputes  have  arisen  about  misconceptions  of  this 


PREFACE.  11 

kind.  The  practical  man  does  not  understand  the  infer- 
ences of  science,  and  considers  himself  bound  to  defend  his 
own  views.  The  contest  is  not  about  scientific  principles, 
which  he  does  not  understand,  but  about  the  false  concep- 
tions he  has  formed  of  them. 

Until  this  contest  is  ended  by  agriculturists  themselves 
taking  an  active  part  in  the  matter,  science  can  offer  no 
effectual  aid.  I  am  doubtful  if  this  time  has  yet  arrived. 
I  built  my  hopes,  however,  on  the  young  generation  who 
enter  upon  practice  with  a  different  preparation  from  their 
fathers.  As  for  myself,  I  have  reached  the  age  when  the 
elements  of  the  mortal  body  betray  a  certain  tendency  to 
commence  a  new  circle  of  action,  when  we  begin  to  think 
about  putting  our  house  in  order,  and  must  defer  to  no 
later  period  what  we  have  still  to  say. 

As  every  investigation  in  agriculture  requires  a  year 
before  we  shall  have  all  the  facts  before  us,  I  have  scarcely 
any  prospect  of  living  to  see  the  results  of  my  teaching. 
The  only  thing  that  remains  for  me  to  do,  under  these  cir- 
cumstances, is  to  place  my  views  in  such  a  manner  be- 
fore the  public,  that  there  can  be  no  possibility  of  mis- 
conception on  the  part  of  those  who  will  give  them- 
selves the  trouble  of  becoming  thoroughly  acquainted 
with  them. 

Many  have  reproached  me  with  unjustly  condemning 
modern  agriculture  as  a  system  of  exhaustion.  From  the 
communications  addressed  to  me  by  many  agriculturists  as 
to  their  system  of  husbandry,  I  must  exempt  them  from 
such  an  accusation.  There  are,  however,  but  few  among 
the  general  body  who  really  know  the  true  condition  of 
their  soil. 

I  have  never  yet  met  with  an  agriculturist  who  kept  a 
ledger,  as  is  done  as  a  matter  of  course  in  other  industrial 
pursuits,  in  which  the  debtor  and  creditor  account  of  every 
acre  of  land  is  entered. 


12  PREFACE. 

The  opinions  of  practical  men  seem  to  be  inherited 
like  some  inveterate  disease.  Each  regards  agriculture 
from  his  own  narrow  point  of  view,  and  forms  his  con- 
clusions of  the  proceedings  of  others  from  what  he  does 
himself. 

JUSTUS  VON  LIEBIG. 

MUNICH  :  March,  1863. 


CONTENTS. 


CHAPTER    I. 

THE   PLANT. 

Chemical  and  cosmic  conditions  of  the  life  of  plants— Conditions  for  the  germina- 
tion of  the  seed  ;  moisture  and  oxygen,  their  action — Influence  of  the  seed  in 
the  formation  of  the  organs  of  absorption,  and  the  production  of  varieties  ; 
influence  of  climate  and  soil  in  producing  varieties— Importance  of  a  knowl- 
edge of  the  developement  of  roots  ,  radication  of  different  plants— Comparison 
of  the  process  of  vegetation  in  annual,  biennial  and  perennial  plants — Growth 
of  the  asparagus,  as  an  example  of  a  perennial  plant ;  storing  of  reserved  food 
in  its  underground  organs  ;  use  of  this  store — Meadow  and  woody  plants- 
Growth  of  biennial  plants  ;  turnips  :  Anderson's  experiments — Growth  of  an- 
nual plants  ;  summer  plants  :  tobacco  ;  winter  wheat,  its  developement  like 
biennial  plants.;  oats ;  Arendt's  experiments  ;  Knopp's  experiments  with 
maize  in  flower— The  protoplastem  (matter  for  forming  cells)  ;  conditions  for 
its  formation  ;  Boussingault's  experiments  ;  organic  processes  in  plants,  di- 
rected to  the  formation  of  the  protoplastem— Absorption  of  food  by  plants  not 
an  osmotic  process  ;  marine-plants  ;  duck-weed  ;  land-plants  ;  Hale's  experi- 
ments on  absorption  by  the  roots  and  evaporation  from  the  leaves— Power  of 
the  root  to  exclude  certain  substances  from  absorption  not  absolute  ;  Forch- 
hammer,  Knopp — Comportment  of  the  roots  of  land  and  water  plants  to  solu- 
tions of  salts  ;  De  Saussure,  Schlossberger  ;  comportment  of  land-plants  to  so- 
lutions of  salts  in  the  soil — Use  of  those  mineral  matters  which  are  constant  in 
different  species  of  plants  ;  iron,  magnesia,  iodine,  and  chlorine  compounds — 
Absorption  of  matters  by  plants  from  the  surrounding  medium  ;  influence  of 
the  consumption  of  them  by  the  plant ;  part  played  by  the  roots  in  their  ab- 
eorption,  .........  PAGE  19 

CHAPTER  II. 

THE   SOIL. 

The  soil  contains  the  food  of  plants— Soil  and  subsoil ;  conversion  of  the  latter  into 
the  former — Power  of  the  soil  to  withdraw  the  food  of  plants  from  solution  In 


14  CONTENTS. 

pure  and  in  carbonic  acid  water  ;  similar  action  of  charcoal ;  process  of  surface 
attraction ;  chemical  decomposition  often  accompanies  this  attraction  of  the 
food  of  plants  in  the  soil ;  general  resemblance  of  the  soil  in  its  action  to  ani- 
mal charcoal — All  arable  soils  possess  the  power  of  absorption,  but  in  different 
degrees — Mode  of  the  distribution  of  the  food  of  plants  in  the  soil ;  chemically 
and  physically  fixed  condition  of  the  food— Only  the  physically  fixed  are  avail- 
able to  plants,  being  made  soluble  by  the  roots — Power  of  the  soil  to  nourish 
plants  ;  on  what  dependent— Comportment  of  an  exhausted  soil  in  fallow- 
Means  for  making  the  chemically  fixed  elements  of  food  available  to  plants- 
Action  of  air,  weather,  decaying  organic  matters  and  chemical  means— Distri- 
bution of  phosphoric  and  silicic  acids ;  influence  of  organic  matters — Action  of 
lime— Process  of  the  absorption  of  food  from  the  soil  by  the  extremities  of  the 
roots— Mechanical  preparation  of  the  soil ;  its  influence  on  the  growth  of 
plants  ;  chemical  means  for  preparing  the  soil— Rotation  of  crops  ;  its  influ- 
ence on  the  quality  of  the  soil ;  action  of  draining — Plants  do  not  receive  their 
food  from  a  solution  circulating  in  the  soil ;  examination  of  drain,  lysimeter, 
spring  and  river  water  :  bog  water,  food  of  plants  contained  in  it ;  Briickenauer 
spring  water  contains  volatile  fatty  acids  ;  amount  of  food  of  plants  in  natural 
waters  dependent  on  the  nature  of  the  soil  through  which  they  flow— Mud  and 
bog  earth  as  manure  ,  explanation  of  their  action— Manner  in  which  plants 
take  up  their  food  from  the  soil ;  experiments  on  the  growth  of  plants  in  solu- 
tions containing  their  food  ;  similar  experiments  with  soil  containing  the  food 
in  a  physically  fixed  state — Intimate  connection  of  natural  laws — Average 
crop  ;  necessary  quantity  of  assimilable  food  in  the  soil  for  the  production  of 
such  ;  importance  of  the  extent  of  surface  of  the  food  in  the  soil ;  the  root  sur- 
face—Quantity of  food  for  a  given  surface  of  roots  necessary  for  a  wheat  or 
rye  crop— Analysis  of  the  soil  of  a  field— Difference  between  fertility  and  pro- 
ductive power  of  a  field — Mode  of  estimating  relative  extent  of  root  surfaces 
— Conversion  of  rye  into  wheat  soil ;  quantity  of  food  necessary  for  the  pur- 
pose ;  the  plan  impracticable— Immobility  in  the  soil  of  the  food  of  plants  ;  ex- 
perience in  agriculture— Real  and  ideal  maximum  production— Conversion  in 
practice  of  the  chemically  fixed  food  into  an  available  form — Effect  of  a  manure 
depends  upon  the  property  of  the  soil — Improper  relative  proportions  of  the 
different  elements  of  food  in  the  soil :  effect  of  this  upon  the  different  culti- 
vated plants  :  means  for  restoring  the  proper  relative  proportions,  .  .  73 


CHAPTER  HI. 

ACTION   OP   SOIL   ON   FOOD   OF   PLANTS   IN   MANURE. 

Manures  :  meaning  of  the  term  ;  their  action  as  food  of  plants  and  means  for  im- 
proving the  soil — Effect  on  soils  with  different  powers  of  absorption— Each  soil 
possesses  a  definite  power  of  absorption  ;  the  distribution  of  the  food  of  plants 
in  the  soil  is  inversely  to  the  power  of  absorption  ;  means  of  counteracting  the 
absorptive  power — Absorption  number,  notion  of;  comparison  of  in  different 
fields  ;  its  importance  in  husbandry— Soil  saturated  with  food  of  plants  ;  its 
comportment  with  water— Quantity  of  food  to  saturate  a  soil— A  saturated 
eoil  not  required  for  the  growth  of  plants — Manuring  may  be  compared  to  the 
application  of  earth  saturated  with  food— Importance  of  the  uniform  distribu- 
tion of  food  in  manures ;  fresh  and  rotted  stall  manure  ;  compost ;  importance 
of  powdered  turf  for  the  preparation  of  manure— Quantity  of  food  in  tin- 


CONTENTS.  15 

manured  fields  and  their  powers  of  production;  increase  of  the  latter  appar- 
ently out  of  proportion  to  the  manure  added ;  experiments  on  this  point  • 
explanation  ;  composition  of  the  soil  and  its  absorptive  power  compared  with 
the  requirements  of  the  plants  to  be  cultivated  on  it ;  surface  and  subsoil 
plants,  the  tillage  and  manuring  respectively  required  by  each  —  Clover 
sickness ;  experiments  of  Gilbert  and  Lawes  ;  their  conclusions  ;  value  of 
them,  ...  134 


CHAPTER  IV. 

FARM-YARD   MANURE. 

The  fertility  of  a  soil  depends  upon  the  sum  of  available  food,  the  continuance  of 
the  fertility  upon  the  total  amount  of  all  food  in  it— Chemical  and  agricultural 
exhaustion  of  the  soil — Exhaustion  of  the  soil  by  cultivation,  laws  regulating 
its  progression  ;  effect  of  the  transformation  in  the  soil  of  the  chemically  fixed 
into  physically  fixed  elements  of  food  ;  effect  on  the  progress  of  exhaustion  by 
partial  restoration  of  the  withdrawn  food  of  plants— Progress  of  the  exhaustion 
by  different  cultivated  plants — Cultivation  of  cereals,  consequence  of  removing 
the  grain  and  leaving  the  straw  in  the  soil ;  intervening  clover  and  potato 
crops  ,  effect  of  leaving  in  the  ground  the  whole  or  a  portion  of  these  crops  ; 
division  of  soils  ;  productive  power  of  wheat  fields  increased  by  accumulating 
in  them  the  materials  derived  from  clover  and  potato  fields  ;  cultivation  of 
fodder  plants  ;  their  food  partly  derived  from  the  subsoil ;  addition  of  these  in- 
creases the  productive  power  of  the  surface  soil— Natural  connection  between 
the  cultivation  of  cereals  and  fodder  plants,  the  influence  on  the  fertility  of 
land — Exhaustion  of  the  soil  rcamoved  by  the  restoration  of  the  withdrawn 
mineral  constituents  ;  the  excrement  of  men  and  animals  contains  these  ;  their 
restoration  depends  upon  the  agriculturist,  .  .  .  .  .164 


CHAPTER  V. 

THE   SYSTEM   OP   FARM-YARD   MANURING. 

Questions  to  be  solved— Experiments  of  Renning,  their  significance— Produce  of 
unmanured  fields— Influence  of  preceding  crops,  of  the  situation,  and  climatic 
conditions,  on  the  produce— Each  field  possesses  its  own  power  of  production 
— Large  crops,  their  dependence  and  continuation — Closeness  of  the  food  of 
plants,  what  is  meant  thereby— The  closeness  of  the  particles  of  food  in  the 
soil  is  in  proportion  to  the  produce— Produce  of  corn  and  straw  influenced  by 
the  relations  of  the  assimilated  food  and  by  the  conditions  of  growth  ;  action 
of  food  supplied  in  manures — Potatoes,  oats,  and  clover  crops  of  the  Saxon 
fields  ;  conclusions  drawn  from  them  as  to  the  condition  of  the  fields— Produce 
of  these  fields  from  farm-yard  manure ;  the  increase  of  produce  cannot  be  cal- 
culated from  the  amount  of  manure  used— Restoration  of  the  power  of  produc- 
tion of  exhausted  fields  by  the  increase  of  the  necessary  elements  of  food  pres- 
ent in  the  soil  in  minimum  amount ;  advantageous  use  of  farm-yard  manure 
in  this  respect ;  explanation  of  the  result — Action  of  manure  as  compared  with 
quantity  used  :  experiments — Rational  system  of  cultivation — Depth  to  which 
the  food  of  plants  penetrates  is  dependent  on  the  power  of  absorption  of  the 


16  CONTENTS. 

soil ;  the  Saxon  fields  considered  in  this  respect ;  the  power  of  absorption  con- 
sidered in  manuring— Change  produced  in  the  composition  of  the  soil  by  the 
system  of  farm-yard  manuring  ;  the  different  stages  of  this  system,  the  fina1 
result — Examples  of  these  stages  in  the  Saxon  experimental  fields — Cause  of 
the  growth  of  weeds  ;  remedies — The  history  of  husbandry,  what  is  taught  by 
it — Present  condition  of  European  husbandry — Present  production  ot  the  land 
compared  with  the  earlier  ;  conclusions — Continuation  of  production  regulated 
by  a  natural  law — Law  of  restoration  ;  defective  practice  of  it— Agricul-.ure  in 
the  time  of  Charlemagne— Agriculture  in  the  Palatinate— Corn  fields  in  the 
valleys  of  the  Nile  and  Ganges  ;  nature  provides  in  them  for  the  restoration  of 
food  of  plants — Practical  agriculture  and  the  law  of  restoration — The  sta- 
tistical returns  of  average  crops  afford  an  explanation  of  the  condition  of  corn 
fields,  .  * 184 


CHAPTER  VI. 

GUANO. 

Composition  compared  with  that  of  seeds  ;  small  amount  of  potash  in  it ;  its  ac- 
tion—Guano and  bone-earth,  similarity  of  their  active  ingredients— Guano 
acts  quicker  than  bone-earth,  or  a  mixture  of  the  latter  and  ammoniacal  salts  , 
reason  of  this— Oxalic  acid  in  Peruvian  guano  ;  the  phosphoric  acid  rendered 
soluble  by  its  means— Peruvian  guano,  its  effect  on  the  cultivation  of  corn- 
Moist  guano  loses  ammonia — Moistening  guano  with  water  acidulated  with 
sulphuric  acid ;  effect— Inactivity  of  guano  in  dry  and  very  wet  weather- 
Rapidity  of  its  action  as  a  manure,  on  what  dependent— Comparison  of  the 
effect  of  farm-yard  manure  and  guano  ;  effect  produced  by  mixing  the  two- 
Guano  on  a  field  rich  in  ammonia— Increased  produce  by  guano,  what  it  pre- 
supposes—Exhaustion of  the  soil  by  continuous  use  of  guano— Mixture  of 
guano  with  gypsum  and  with  sulphuric  acid— The  Saxon  agricultural  experi- 
ments; their  results,  ...  245 


CHAPTER  VII. 

POUDRETTE — HUMAN   EXCREMENTS. 

Poudrette,  nature  of  ;  small  amount  of  the  food  of  plants  in  it— Human  excrement, 
its  value— Construction  of  the  privies  in  the  barracks  at  Rastadt— Calculation 
of  the  amount  of  corn  produced  by  the  excrement  collected  ;  importance  to  the 
neighbourhood— Its  effect  not  impaired  by  deodorising  with  sulphate  of  iron — 
The  excrement  of  the  inhabitants  of  towns  as  manure— Its  importance,  .  258 

CHAPTER  VIII. 

EARTHY    PHOSPHATES. 

High  agricultural  value  of  phosphates— Phosphates  of  commerce  ;  selection  of  the 
kind  to  be  used  dependent  on  the  object  in  view,  and  on  the  nature  of  the  soil— 
The  rapidity  and  the  duration  of  the  effect  of  the  neutral  and  of  the  soluble 
phosphate  (superphosphate)  of  lime— The  Saxon  manuring  experiments,  262 


CONTENTS.  17 


CHAPTER  IX. 

GROUND    RAPE-CAKE. 

Nature  and  composition  of ;  the,  diffusibility  of  its  constituents  in  the  soil  is  com- 
paratively great— Its  importance  as  a  manuring  agent  is  small— The  Saxon 
agricultural  experiments  with  rape-cake — The  inferences  from  them,  .  267 

CHAPTER  X. 

WOOD-ASH. 

The  amount  of  the  food  of  plants  in  it— Box- wood  ash  gives  only  the  half  of  its 
potash  readily  to  water— Convenience  in  mixing  wood-ash  with  earth  before 
applying  it — Lixiviated  ash,  its  value — Proper  mode  of  applying  ashes  as  a 
manure,  ..........  272 

CHAPTER  XI. 

AMMONIA   AND   NITRIC   ACID. 

Source  of  the  nitrogen  of  plants— Amount  of  ammonia  and  nitric  acid  in  rain  and 
dew  :  Bineau,  Boussingault,  Knop — Quantity  of  ammonia  in  the  air— Quantity 
of  nitrogenous  food  brought  to  the  soil  yearly  by  rain  and  dew  ;  more  present 
in  the  soil  than  is  removed  by  the  crops— The  general  reason  for  decrease  of 
productive  power  in  soils— Classification  of  manures  according  to  the  amount 
of  nitrogen  ;  assimilable  and  sparingly  assimilable  nitrogen  ;  the  nitrogen 
theory  ;  only  ammonia  according  to  this  theory  is  wanting ;  resemblance  to 
the  humus  theory— Manuring  experiments  with  compounds  of  ammonia  by 
Schattenmann,  by  Lawes  and  Gilbert,  by  the  Agricultural  Union  of  Munich, 
and  by  Kuhlmann— The  efficacy  of  a  manure  is  not  in  proportion  to  its  amount 
of  nitrogen  .  experiments— Large  amount  of  nitrogen  in  soils  :  the  experiments 
of  Schmid  and  Pierre ;  the  arable  surface  soil  contains  most  nitrogen— Form 
of  the  ammonia  in  the  soil ;  Mayer's  experiments— Comportment  of  soil  and 
farm-yard  manure  with  the  alkalies— The  ineffective  nitrogen  of  the  soil  made 
effective  by  the  supply  of  ash-constituents  that  are  wanting— Progress  in  ag- 
riculture impossible  if  dependent  on  a  supply  of  ammoniacal  compounds  ;  re- 
sults of  Lawes'  experiment  with  salts  of  ammonia— The  artificial  supply  of 
ammoniacal  manures  contrasted  with  the  crops  produced  and  the  increase  of 
population— Increase  of  nitrogenous  food  by  natural  means ;  formation  of 
nitrite  of  ammonia  by  oxidation  in  the  air  according  to  Schonbein— Supply  of 
food  in  excess  necessary  to  produce  corn-crops  ;  reasons — How  the  necessary 
excess  of  nitrogenous  food  for  corn  maybe  obtained  from  natural  sources — The 
supply  of  nitrogen  in  farm-yard  manure  in  the  Saxon  experiments  correspond- 
ed to  the  crop  of  clover-hay— Loss  of  nitrogen  in  lime  soils  by  oxidation ; 
utility  of  a  supply  of  nitrogen  to  such  soils— Effect  of  nitrogenous  food  on  the 
aspect  of  young  plants  ;  on  potatoes— Empirical  and  rational  systems  of  agri- 
culture, .  274 


18  CONTENTS. 

CHAPTER  XII. 

COMMON   SALT,    NITRATE   OF   SODA,    SALTS   OP   AMMONIA,    GYPSUM,    LIME. 

Effect  of  these  substances  as  elements  of  food  ;  their  effect  on  the  condition  of  the 
soil — Kuhlmaim's  experiments  with  common  salt,  nitrate  of  soda,  and  salts  of 
ammonia ,  experiments  with  the  same  substances  in  Bavaria ;  conclusions  : 
these  matters  are  elements  of  food  ;  they  are  chemical  means  for  preparing  the 
soil ;  they  cause  the  distribution  of  the  food  in  the  soil  in  the  form  proper  for 
the  growth  of  plants — Experiments  by  Pincus  with  gypsum  and  sulphate  of 
magnesia  on  clover;  decrease  of  flowers  and  increase  of  stem  and  leaves  of 
clover  by  sulphates  ;  the  crop  is  not  in  proportion  to  the  quantity  of  sulphates 
used— Effect  of  gypsum  not  yet  explained ;  indication  in  the  comportment  of 
clover  soils  with  solution  of  gypsum ;  such  solution  disperses  potash  and 
magnesia  in  the  soil — Manures,  their  effect  not  explained  by  the  composition  of 
plants  produced  by  them — Composition  of  the  ash  of  clover  manured  with  dif- 
ferent substances— Effect  of  lime  ;  experiments  of  Kuhlmann  and  Trager  ; 
comportment  of  lime-water  with  soils,  ^.  -  .,.->  l  .  '  •  ,  .  316 

APPENDICES. 

Beech  leaves  and  asparagus,  their  ash-constituents  at  different  periods  of  growth — 
The  amylum  of  the  palm— Motion  of  sap  in  plants— Drain,  lysimeter,  river,  and 
bog  water,  their  constituents — Fontinalis  antipyretica  from  two  different  waters, 
ash-constituents— Vegetation  of  maize  in  solutions  of  its  food— Experiments  on 
the  growth  of  beans  in  pure  and  prepared  turf,  results— Japanese  agriculture — 
The  cultivated  soil  of  the  torrid  zone,  its  exhaustibility,  its  manure— Analysis 
of  clover  by  Pincus— Clover  sickness,  its  causes,  .  .  332 


NATURAL  LAWS  OF  HUSBANDRY. 


CHAPTER   I. 


THE   PLANT. 

Chemical  and  cosmic  conditions  of  the  life  of  plants— Conditions  for  the  germina- 
tion of  the  seed  ;  moisture  and  oxygen,  their  action— Influence  of  the  seed  in 
the  formation  of  the  organs  of  absorption,  and  the  production  of  varieties  ; 
influence  of  climate  and  soil  in  producing  varieties— Importance  of  a  knowl- 
edge of  the  developement  of  roots  ;  radication  of  different  plants— Comparison 
of  the  process  of  vegetation  in  annual,  biennial  and  perennial  plants— Growth 
of  the  asparagus,  as  an  example  of  a  perennial  plant  •  storing  of  reserved  food 
in  its  underground  organs  ;  use  of  this  store — Meadow  and  woody  plants- 
Growth  of  biennial  plants  ;  turnips  :  Anderson's  experiments — Growth  of  an- 
nual plants  ;  summer  plants  :  tobacco  ;  winter  wheat,  its  developement  like 
biennial  plants  ;  oats  ;  Arendt's  experiments  ;  Knopp's  experiments  with 
maize  in  fiower— The  protoplastem  (matter  for  forming  cells)  ;  conditions  for 
its  formation  ;  Boussingault's  experiments  ;  organic  processes  in  plants,  di- 
rected to  the  formation  of  the  protoplastem — Absorption  of  food  by  plants  not 
an  osmotic  process  ;  marine-plants  ;  duck- weed  ;  land-plants  ;  Hale's  experi- 
ments on  absorption  by  the  roots  and  evaporation  from  the  leaves — Power  of 
the  root  to  exclude  certain  substances  from  absorption  not  absolute  ;  Forch- 
hammer,  Knopp — Comportment  of  the  roots  of  land  and  water  plants  to  solu- 
tions of  salts  ;  De  Baussure,  Schlossberger ;  comportment  of  land-plants  to  so- 
lutions of  salts  in  the  soil — Use  of  those  mineral  matters  which  are  constant  in 
different  species  of  plants  ;  iron,  magnesia,  iodine,  and  chlorine  compounds — 
Absorption  of  matters  by  plants  from  the  surrounding  medium  ;  influence  of 
the  consumption  of  them  by  the  plant ;  part  played  by  the  roots  in  their  ab- 
sorption. 

TO  obtain  a  clear  view  of  the  theory  and  practice  of 
Agriculture,  we  must  keep  in  mind  the  most  general 
chemical  conditions  of  the  life  of  plants. 

Plants  contain  combustible  and  incombustible  con- 
stituents. Of  the  latter,  which  compose  the  ash  left  by 
all  parts  of  a  plant  on  combustion,  the  most  essential 
elements  are—phosphoric  acid,  sulphuric  acid,  silicic 
acid,  potash,  soda,  lime,  magnesia,  iron,  and  chloride 
of  sodium. 


ZU  THE  PLANT. 

The  combustible  constituents  are  derived  from  car- 
bonic acid,  ammonia,  sulphuric  acid,  and  water. 

By  the  vital  process  of  vegetation,  the  body  of  the 
plant  is  formed  from  these  materials,  which  are  there- 
fore called  the  food  of  plants.  All  the  materials  con- 
stituting the  food  of  our  cultivated  plants  belong  to  the 
mineral  kingdom.  The  gaseous  elements  are  absorbed 
by  the  leaves,  the  fixed  elements  by  the  roots  ;  the  for- 
mer, however,  being  often  constituents  of  the  soil  also, 
may  reach  the  plant  by  the  roots,  as  well  as  by  the 
leaves. 

The  gaseous  elements  form  component  parts  of  the 
atmosphere,  and  are,  from  their  nature,  in  continual 
motion.  The  fixed  elements  are,  in  the  case  of  land- 
plants,  constituents  of  the  soil,  and  cannot  of  themselves 
leave  the  spot  in  which  they  are  found.  The  cosmic 
conditions  of  vegetable  life  are  heat  and  sunlight. 

By  the  cooperation  of  the  cosmic  and  the  chemical 
conditions,  the  perfect  plant  is  developed  from  the  germ 
or  seed.  The  seed  contains,  within  its  own  substance, 
the  elements  required  to  form  the  organs  which  are  in- 
tended to  take  up  food  from  the  air  and  the  soil.  These 
elements  are  nitrogenous  substances,  similar  in  compo- 
sition to. the  casein  of  milk  or  the  albumen  of  the  blood ; 
and  also  starch,  fat,  gum,  or  sugar,  with  a  certain  quan- 
tity of  earthy  phosphates  and  alkaline  salts.  The  fari- 
naceous body,  or  so-called  albumen  of  the  seed  of  corn, 
as  also  the  constituents  of  the  cotyledons  in  leguminous 
plants,  become  the  roots  and  leaves  of  the  nascent  plant. 
If  corn-seeds  are  set  to  germinate  in  water,  and  allowed 
to  grow  upon  a  glass  plate  furnished  with  fine  perfora- 
tions, through  which  the  roots  may  reach  the  water, 
the  grain  will  go. on  growing  for  several  weeks  without 
receiving  any  incombustible  element  of  food  or  any 
constituent  of  the  soil.  After  three  or  four  weeks  the 
apex  of  the  first  leaf  is  seen  to  turn  yellow  ;  and  upon 
examining  the  seed,  nothing  but  an  empty  skin  is  found, 
for  the  starch  has  disappeared  together  with  the  cellu- 
lose (Mitscherlich).  However,  the  plant  does  not  die 
away,  but  new  leaves  are  produced,  often  also  a  feeble 


GERMINATION   AND   GROWTH   OF   THE   SEED.  21 

stalk ;  the  constituents  of  the  first-formed,  but  now 
withering,  leaves  being  applied  to  the  formation  of 
fresh  shoots. 

Under  favourable  circumstances,  seeds  with  very 
large  and  vigorous  cotyledons  abounding  in  nutritive 
matter  (e.  g.  beans)  may,  by  vegetation  in  water  alone, 
be  got  to  flower — nay,  even  actually  to  produce  small 
seeds ;  this  developement,  however,  is  mostly  unat- 
tended by  a  perceptible  increase  of  substance,  but  do- 
pends  solely  upon  a  mere  transposition  of  the  elements 
of  the  seed. 

Nutrition  is  a  process  by  which  food  is  assimilated ; 
a  plant  grows  when  its  mass  is  augmented,  and  its  mass 
is  increased  by  absorbing  materials  from  without,  which 
are,  from  their  nature,  suited  to  become  constituent  ele- 
ments of  the  body  of  the  plant,  and  to  sustain  those 
functions  upon  which  their  assimilation  depends. 

The  bud  on  a  potato-tuber  stands  in  the  same  rela- 
tion to  the  constituents  of  the  tuber  as  the  germ  in  a 
corn-seed  does  to  the  farinaceous  matter  of  the  albumen. 
"While  the  bud  is  developed  in  the  formation  of  the 
young  plant,  the  amylum  and  the  nitrogenous  and  min- 
eral constituents  of  the  sap  of  the  tuber  are  employed 
to  form  the  young  branches  and  leaves.  A  potato, 
which  lay  wrapt  up  in  thick  paper,  in  a  box,  in  the 
Chemical  Laboratory  at  Giessen — in  a  place  absolutely 
dark,  dry,  and  warm,  where  the  atmosphere  was  seldom 
changed — was  found  to  have  produced,  from  each  bud, 
a  simple  white  shoot  many  feet  long,  showing  no  traces 
of  leaves,  but  covered  with  hundreds  of  minute  potatoes, 
which  exhibited  the  same  internal  structure  as  tubers 
grown  in  a  field ;  the  cells  consisted  of  cellulose,  and 
were  filled  with  minute  starch  granules.  It  is  certain 
that  the  starch  of  the  mother  tuber,  to  have  moved 
away  from  its  position,  must  have  become  soluble  ;  but 
it  is  equally  clear  that  in  the  developement  of  the 
shoots  a  cause  was  operative  within  them,  which  (in  the 
absence  of  all  outward  causes  whereon  growth  depends) 
reconverted  the  dissolved  constituents  of  the  mother 
tuber  into  cellulose  and  starch  granules. 


22  THE  PLANT. 

The  conditions  required  for  the  germination  of  a 
seed  are — moisture,  a  certain  degree  of  heat,  and  access 
of  air ;  where  one  of  these  conditions  is  excluded,  the 
seed  will  not  germinate.  By  the  influence  of  the  moist- 
ure which  the  seed  absorbs,  and  which  causes  it  to 
swell,  a  chemical  action  takes  place  in  it ;  one  of  the 
nitrogenous  constituents  acts  upon  the  others,  and  upon 
the  amylum,  so  that  by  a  transposition  of  the  element- 
ary particles,  the  constituents  are  rendered  soluble  ;  the 
gluten  is  converted  into  vegetable  albumen ;  the  amy- 
lum and  oil  into  sugar.  If  the  oxygen  of  the  air  is  ex- 
cluded, the  changes  either  do  not  take  place  or  they 
proceed  in  a  different  way.  The  seeds  of  land-plants, 
when  submersed  under  water,  or  placed  in  a  soil  cov- 
ered with  stagnant  water,  which  excludes  the  air,  wrill 
not-  put  forth  their  plumules.  This  is  the  cause  why 
many  seeds,  lying  deep  in  the  ground  or  in  bogs,  will 
remain  for  many  years  without  germinating,  although 
the  conditions  of  moisture  and  temperature  be  favour- 
able. It  is  often  found  that  earth  taken  up  from  bogs, 
or  brought  up  by  the  plough  from  the  deep  subsoil,  and 
exposed  to  the  atmosphere,  becomes  covered  with  vege- 
tation, arising  from  seeds  which,  for  their  develope- 
ment,  required  free  access  of  air.  Lowness  of  tempera- 
ture tends  to  annul  or  retard  the  influence  of  the  air 
upon  the  process  of  germination ;  whilst  increase  of 
temperature,  with  a  proper  supply  of  moisture,  acceler- 
ates the  chemical  changes  in  the  seed.  No  seed  germi- 
nates below  32°  Fahrenheit ;  each  germinates  at  a  defi- 
nite temperature,  and  therefore  in  fixed  seasons  of  the 
year.  The  seeds  of  Vicia  fdba,  Phaseolus  vulgaris, 
and  the  poppy,  lose  the  power  of  germinating  when 
dried  at  95°  Fahrenheit ;  while  barley,  maize,  lentil, 
hemp,  and  lettuce  seed  retain  the  power  at  that  heat ; 
but  wheat,  rye,  vetch,  and  cabbage  seed  will  germinate 
even  at  158°  Fahrenheit. 

During  germination,  oxygen  is  taken  up  from  the 
air  around  the  seed,  and  an  equal  volume  of  carbonic 
acid  is  evolved. 

If  seeds  are  set  to  germinate  in  glasses,  with  a  slip 


PROCESS   OF   GEEMINATION.  23 

of  litmus  paper  fastened  on  the  inside,  the  paper  is  red- 
dened, often  after  a  very  short  time,  owing  to  the  dis- 
engagement of  acetic  acid :  the  most  abundant  and 
rapid  evolution  of  free  acid  was  found  to  take  place  in 
the  germination  of  cruciferous  plants,  cabbage,  and 
rape-seed  (Becquerel,  Edwards).  Certain  it  is  that  the 
fluid  contents  of  the  cells  of  the  roots,  as  well  as  the  sap 
of  most  plants,  have  an  acid  reaction,  from  the  presence 
of  a  non-volatile  acid ;  the  sap  of  the  young  spring 
shoots  of  the  vine  yields,  upon  evaporation,  an  abun- 
dant crystallization  of  bitartrate  of  potash. 

By  the  experiments  of  Decandolle  and  Macaire, 
which  have  not  yet  been  controverted,  it  was  shown 
that  vigorous  plants  of  C/iondrilla  muralis  and  Phaseo- 
lus  vulgaris  which  had  been  taken  from  the  ground, 
with  their  roots,  and  were  allowed  to  vegetate  in  water, 
imparted  to  the  water,  after  a  week's  time,  a  yellowish 
tint,  a  smell  like  that  of  opium,  and  a  harsh  taste : 
whereas  when  the  root  was  cut  off  at  the  stalk  and  both 
were  placed  in  water,  no  such  substances  were  given  off 
as  those  which  the  entire  plant  had  yielded. 

Lettuces  and  other  plants,  when  taken  out  of  the 
gound,  and,  with  their  roots  previously  washed  clean, 
are  allowed  to  vegetate  in  blue  litmus  tincture,  will 
continue  to  grow  in  the  liquid,  apparently  at  the  ex- 
pense of  the  constituents  of  the  lower  leaves,  which 
wither  awray.  After  three  or  four  days  the  litmus  tinc- 
ture assumes  a  red  colour,  which,  however,  disappears 
again  upon  boiling  the  fluid :  this  would  seem  to  indi- 
cate that  the  roots  had  given  off  carbonic  acid.  If  the 
plants  are  left  longer  in  the  litmus  tincture,  the  latter 
suffers  decomposition,  and  becomes  neutral  and  colour- 
less, while  the  colouring  matter,  separating  in  flakes, 
gathers  round  the  fibres  of  the  roots. 

The  developement  of  a  plant  depends  upon  its  first 
radication,  and  the  choice  of  proper  seeds  is  therefore 
of  the  highest  importance  for  the  future  plant.  A  crop 
of  the  same  wheat,  reaped  in  the  same  year,  and  from 
the  same  field,  will  exhibit  differences  in  the  size  of 
the  grains,  some  being  larger,  others  smaller;  and 


24:  THE   PLANT. 

among  both  kinds,  some  when  broken  up  will  present  a 
mealy,  others  a  horny  appearance,  the  one  being  more, 
the  others  less  completely  developed.  The  cause  is 
this — that  the  stalks  in  the  same  field  do  not  all  shoot 
into  ear  and  flower  at  the  same  time,  and  that  some  of 
them  produce  seeds  much  more  maturely  than  others : 
hence  the  seeds  of  the  one  are  far  more  developed,  even 
in  unfavourable  weather,  than  the  seeds  of  the  others. 
A  mixture  of  seeds  unequal  in  their  developement,  or 
differing  in  the  quantities  of  amylum,  gluten,  and  inor- 
ganic matters  which  they  severally  contain,  will  pro- 
duce a  crop  of  plants  as  unequal  in  their  developement 
as  the  original  seeds  from  which  they  sprung. 

The  strength  and  number  of  tne  roots  and  leaves 
formed  in  the  process  of  germination  are  (as  regards  the 
non-nitrogenous  constituents)  in  direct  proportion  to  the 
amount  of  amylum  in  the  original  seed.  A  seed  poor 
in  amylum  will,  indeed,  germinate  in  the  same  fashion 
as  another  seed  abounding  in  it ;  but  by  the  time  the 
former  has  succeeded,  by  the  absorption  of  food  from 
without,  in  producing  roots  and  leaves  as  strong  and 
numerous,  the  plant  grown  from  the  more  amylaceous 
seed  is  again  just  as  much  more  advanced  in  growth : 
its  food-absorbing  surface  was  larger  from  the  begin- 
ning, and  the  growth  of  the  young  plant  is  in  like  pro- 
portion. 

Poor  and  sickly  seeds  will  produce  stunted  plants, 
which  again  will  yield  seeds  bearing  in  a  great  measure 
the  same  character. 

The  horticulturist  knows  the  natural  relation  which 
the  condition  of  the  seed  bears  to  the  production  of  a 
plant,  which  is  to  possess  all  or  only  some  properties  of 
the  species  :  just  as  the  cattle-breeder,  who,  with  a  view 
to  propagation  and  increase  of  stock,  selects  only  the 
healthiest  and  best-formed  animals  for  his  purpose ;  the 
gardener  is  aware  that  the  flat  and  shining  seeds  in  the 
pod  of  a  stock  gilly-flower  will  give  tall  plants  with 
single  flowers,  while  the  shrivelled  seeds  will  furnish 
low  plants  with  double  flowers  throughout. 

The  influence  of  soil  and  climate  gives  rise  to  differ- 


IMPORTANCE   OF   GOOD    SEEDS.  25 

ent  varieties  of  plants,  which,  like  races,  are  possessed 
of  certain  peculiarities,  and  are  propagated  by  means 
of  seed,  as  long  as  the  conditions  remain  the  same. 
Planted  in  another  soil,  or  in  a  different  climate,  the 
new  variety  will  lose  again  some  one  or  other  of  its  dis- 
tinguishing characteristics. 

The  influence  exerted  by  the  condition  of  the  soil  in 
producing  varieties  of  plants  is  observed  most  fre- 
quently with  seeds  that  pass  undigested  through  the 
intestinal  canal  of  animals  which  have  eaten  them,  and 
then  receive  a  -different  manuring  according  to  the 
various  nature  of  the  excrements  of  divers  animals  with 
which  they  are  returned  to  the  soil :  an  instance  is 
afforded  by  the  Byrsonima  verbascifolia  (v.  Martius). 

In  the  selection  of  seeds  for  planting  it  is  always 
important  to  take  into  account  the  soil  and  climate 
from  which  they  have  been  derived.  In  England  seed- 
wheat  from  a  poor  soil  is  considered  particularly  well 
suited  to  a  rich  soil ;  rape-seed  grown  in  colder  regions 
or  situations  is  sure  to  give  a  good  crop  in  warmer 
localities.  Clover  seed  and  oats  from  mountainous  dis- 
tricts are  preferred  to  the  same  seeds  from  plains. 
Wheat  from  Odessa  and  from  South  Hungary  is  es- 
teemed in  colder  regions  also.  The  planters  on  the 
Upper  Rhine  import 'their  hemp-seed  from  Bologna 
and  Ferrara. 

In  like  manner  many  German  flax-growers,  who 
wish  to  produce  tall  plants  of  uniform  size,  attach  par- 
ticular value  to  linseed  from  Courland  and  Livonia, 
where  the  soil  and  the  nature  of  the  climate,  especially 
the  short  hot  summer,  bring  the  flowering  and  fruit 
time  near  together  ;  so  that  the  flowers,  being  simulta- 
neously and  uniformly  fructified,  produce  ripe  and  per- 
fect seeds. 

Everyone  knows  how  much  the  weather,  during  the 
flowering  period,  influences  the  formation  of  seed.  If, 
after  the  flowering  has  commenced,  cold  weather  or 
rain  sets  in,  retarding  the  full  developement  of  the  in- 
florescence, the  flowers  fertilised  at  a  later  period  pro- 
duce no  seeds,  as  the  nutriment  needed  by  them  is 


26  THE   PLANT. 

applied  by  the  flowers  first  fertilised  for  their  own  de- 
velopement.  It  is  a  fact,  that  many  plants  will  not 
repay  the  trouble  of  cultivation,  if  the  climatic  condi- 
tions are  not  sufficiently  favourable  to  effect  the 
thorough  ripening  of  all  the  flowers,  but  serve  only  to 
ripen  part  of  them. 

With  oats  it  often  happens  that  in  warm  moist 
weather  side-branches  will  spring  from  the  axils  of  the 
leaves,  when  the  principal  culm  is  already  shooting 
into  ear ;  whence  it  happens,  that  at  the  end  of  the 
period  of  vegetation  the  plant  is  found  to  bear  both 
ripe  and  unripe  seeds. 

The  condition  of  the  soil,  as  to  porosity  or  compact- 
ness, influences  the  radication  of  plants.  The  fine  fila- 
ments of  the  root,  which  are  often  coated  with  cork-like 
matter,  are  lengthened  by  the  formation  of  new  cells  at 
their  extremities,  and  they  are  obliged  to  exert  a  certain 
pressure,  to  force  their  way  through  the  particles  of 
earth. 

The  root-fibrils  will  always  extend  in  that  direction 
in  which  they  encounter  the  least  resistance  ;  and  this 
lengthening  necessarily  presupposes  that  the  pressure 
wherewith  the  new-formed  cells  push  aside  the  particles 
of  earth,  must  be  somewhat  greater  than  the  cohesion 
of  the  particles.  The  strength  with  which  the  root- 
fibres  force  their  way  through  the  soil,  is  not  equally 
great  in  all  plants.  Those  plants  which  have  roots 
formed  of  very  fine  fibres  are  but  imperfectly  developed 
in  stiff,  heavy  soils,  wherein  other  plants  with  thicker 
and  stiffer  root-fibres  will  grow  luxuriantly.  The  very 
resistance  which  the  heavy  soil  opposes  to  the  spreading 
of  the  roots  of  such  plants  tends  to  strengthen  their 
fibres. 

Of  the  cereals,  wheat,  with  a  comparatively  feeble 
ramification  of  roots  in  the  upper  layers  of  the  soil,  still 
forms  the  strongest  roots,  which  often  penetrate  several 
feet  down  into  the  subsoil ;  for  a  certain  degree  of  com- 
pactness in  the  surface  soil  is  favourable  to  the  devel- 
opement  of  its  roots.  There  are  instances  on  record, 
where  parts  of  a  wheat-field  had  been  trampled  down 


RADICATION    OF   PLANTS.  27 

in  the  winter  by  horses  (by  no  means  an  uncommon 
occurrence  in  the  foxhunting  districts  of  England),  so 
far  as  to  destroy  every  trace  of  a  wheat-plant,  and  yet 
next  year's  crop  turned  out  much  more  abundant  on 
those  very  spots  than  in  any  other  part  of  the  field.  It 
is  evident  that,  to  outlive  an  attack  of  this  kind,  a  plant 
must  have  its  principal  roots  spreading  in  the  deeper 
layers  of  the  soil.  In  the  developement  of  its  roots  and 
the  power  of  penetrating  the  deeper  layers  of  the  soil, 
the  oat-plant  stands  next  to  wheat,  and  will  nourish  in 
a  somewhat  stiff  soil ;  but  as  in  the  superficial  layers 
also  the  roots  of  oats  throw  out  a  number  of  fine  feed- 
ers, in  a  lateral  direction,  it  is  necessary  that  the  top- 
soil  should  be  rather  light  and  open.  A  light,  open 
loam,  even  if  of  no  great  depth,  is  particularly  suited 
for  barley,  which  forms  a  net-work  of  fine  comparatively 
short  root-fibres.  Peas  require  a  loose  soil,  with  little 
cohesion  about  it,  which  will  favour  the  spreading  of 
the  soft  root-fibres  in  the  deeper  layers  also ;  whereas 
the  strong  woody  roots  of  the  horse-bean  will  ramify  in 
all  directions,  even  in  a  heavy  and  more  compact  soil. 
Clover,  grass-seeds,  and  small-sized  seeds  in  general,  put 
forth  at  first  feeble  roots  of  small  extent,  and  require  so 
much  the  greater  care  in  preparing  the  soil,  in  order  to 
ensure  their  healthy  growth.  The  pressure  of  a  layer 
of  earth  half  to  one  inch  thick  suffices  to  prevent  the 
developement  of  the  seed  sown  in  the  ground.  Such 
seeds  require  only  just  as  much  earth  to  cover  them  as 
will  retain  the  needful  moisture  for  germination.  It  is, 
therefore,  found  advantageous  to  sow  clover  together 
with  corn  of  some  kind  ;  for  as  the  corn  is  earlier  and 
quicker  in  growth,  its  leaves  shade  the  young  clover 
plant,  and  protect  it  from  the  too  intense  action  of  the 
sun's  rays ;  thus  affording  more  time  for  the  extension 
and  developement  of  the  roots.  The  nature  of  the 
roots*  of  rapes,  turnips,  and  tuberous  plants,  clearly 
points  out  the  part  of  the  soil  from  which  they  draw 
their  chief  supply  of  food.  Potatoes  are  formed  in  the 

*  Whenever  the  term  '  root '  is  used  in  this  work,  the  underground 
organs  of  plants  are  meant. 


28  THE    PLANT. 

topmost  layer  of  the  soil ;  whereas  the  roots  of  beets 
and  turnips,  sending  their  ramifications  deep  into  the 
subsoil,  will  succeed  best  in  a  loose  soil  of  great  depth. 
Still,  they  will  also  grow  well  in  soil  naturally  heavy 
and  compact,  which  has  been  properly  prepared  for 
their  reception.  Among  turnips,  the  Swedish  variety 
is  distinguished  by  the  numerous  fibres  which  the  root- 
stock  sends  into  the  ground ;  and  mangelwurzel,  with 
its  strong  and  rather  woody  root-fibres,  is  still  better 
suited  than  Swedes  for  a  heavy  clay  soil. 

On  the  length  of  roots  but  few  observations  have 
been  made.  In  some  cases  it  has  been  found  that 
lucerne  will  grow  roots  thirty  feet,  rape  above  five  feet, 
clover  above  six  feet,  lupine  above  seven  feet  in  length. 

A  proper  knowledge  of  the  radication  of  plants  is 
the  groundwork  of  agriculture ;  all  the  operations 
which  the  farmer  applies  to  his  land  must  be  adapted 
to  the  nature  and  conditions  of  the  roots  of  the  plants 
which  he  wishes  to  cultivate.  On  the  root  he  should 
bestow  his  whole  care  ;  upon  that  which  grows  from  it 
he  can  no  longer  exert  any  influence ;  therefore,  to 
secure  a  favourable  result  to  his  labours,  he  should  pre- 
pare the  ground  in  a  proper  manner  for  the  develope- 
ment  and  action  of  the  roots.  The  root  is  not  merely 
the  organ  through  which  the  growing  plant  takes  up 
the  incombustible  elements  of  food  required  for  its 
increase,  but  it  may,  in  another  not  less  important 
function,  be  compared  to  the  flywheel  in  an  engine, 
which  gives  regularity  and  uniformity  to  the  working. 
It  is  in  the  root  that  the  material  is  stored  up  to  supply 
the  growing  plant  with  the  needful  elements  for  con- 
ducting the  processes  of  life,  according  to  the  require- 
ments made  upon  it  by  the  action  of  light  and  heat. 

All  plants  which  give  landscapes  their  peculiar 
character,  and  clothe  the  plains  and  mountain  slopes 
with  perennial  green,  have  an  underground  develope- 
ment,  according  to  the  geological  or  physical  condition 
of  the  soil,  admirably  adapted  to  their  perennial  exist- 
ence and  propagation. 

Whilst  annuals  are  propagated  and  multiplied  by 


KADICATION    OF   DIFFERENT   PLANTS.  29 

seeds  alone,  and  have  always  a  true  root  easily  known 
by  its  simplicity  of  structure,  by  the  absence  of  buds, 
and  by  the  comparatively  short  range  of  its  fibres,  the 
turf-  and  meadow  plants  are  propagated  by  shoots  and 
runners  of  a  peculiar  nature,  and  in  many  of  them 
propagation  is  independent  of  the  formation  of  seed. 

As  the  strawberry,  which  will  in  a  very  short  time 
cover  extensive  tracts  of  ground,  sends  forth  from  the 
stock  above  the  root-bulb  shoots  in  the  shape  of  run- 
ners, which  creeping  along  the  ground,  and  producing 
here  and  there  buds  and  roots,  grow  up  as  independent 
plants,  so  the  perennial  weeds,  among  which  are  here 
included  the  meadow  and  pasture  plants,  spread  in  a 
similar  manner  by  corresponding  underground  organs. 
The  creeping  roots  of  the  couch-grass  (Triticum  repens), 
the  sea  lyme-grass  (Ely mm  arenarius\  the  trefoil  (Tri- 
folium  pratense),  the  common  toad-flax  (Linaria  vul- 
garis),  propagate  their  plants  by  suckers  in  all  direc- 
tions from  the  mother-plant.  The  smooth-stalked 
meadow-grass  (Poa  pratensis)  is  propagated  by  a 
mother-stock,  consisting  of  true  roots,  rooted  runners, 
and  creeping  suckers ;  rye  grass  (Loliwn)  puts  forth 
root-suckers  in  a  stiff  soil,  and  prostrate  stolons  in  loose 
ground.  Cat's-tail  grass  (Phleum)  is  found  sometimes 
with  bulbous,  sometimes  with  fibrous  many-headed 
roots,  having  a  tendency  to  creep  and  to  form  mother- 
stocks.  Timothy-grass  grows  stalk  in  the  first  year ; 
in  the  second,  it  forms  sometimes  bulbous,  sometimes 
fibrous  many-headed  mother-stocks,  which  send  forth 
creepers  in  all  directions.  In  the  same  way,  meadow- 
grass  spreads  partly  by  budding  suckers,  partly  by 
stolons. 

On  comparing  the  vital  processes  in  annual,  bien- 
nial, and  perennial  plants,  we  find  that  the  organic  work 
in  perennials  is  principally  directed  to  the  formation  of 
the  root. 

The  seed  of  asparagus  sown  during  autumn,  in  a 
fertile  soil,  will  produce  next  year,  from  spring  to  the 
end  of  July,  a  plant  about  a  foot  high,  the  stem,  twigs, 
and  leaves  of  which  from  that  time  forward  show  no 


30  THE   PLANT. 

further  increase.  The  tobacco  plant,  which  is  an  an- 
nual, would  from  the  same  period  to  the  end  of  August 
have  produced  a  stem  several  feet  high,  covered  with 
numerous  broad  leaves  ;  and  the  turnip  a  broad  crown 
of  foliage. 

But  the  cessation  in  the  growth  of  the  asparagus 
plant  is  only  apparent ;  for  from  the  moment  that  the 
external  organs  of  nutrition  are  developed,  the  root  in- 
creases in  'extent  and  substance  in  far  greater  propor- 
tion to  the  over-ground  organs  than  is  the 'case  with 
the  tobacco  plant.  The  food  which  the  leaves  have  ab- 
sorbed from  the  air  and  the  roots  from  the  soil,  having 
first  been  transformed  into  organisable  matter,  descends 
to  the  roots,  in  which  there  is  gradually  collected  a, 
sufficient  store  to  enable  the  latter  to  furnish  in  the  fol- 
lowing year  from  themselves  and  without  the  least  sup- 
ply of  food  from  the  atmosphere  the  material  required  for 
the  production  of  a  new  perfect  plant,  with  a  stem  half 
as  high  again  and  a  much  greater  number  of  twigs  and 
leaves.  The  organic  labour  of  this  new  plant,  during 
the  second  year,  results  in  the  generation  again  of 
products  which  are  deposited  in  the  root,  and,  propor- 
tionately to  the  greater  extent  of  the  organs  of  nutrition, 
are  stored  up  in  much  greater  quantity  than  the  roots 
had  originally  supplied. 

The  same  process  is  repeated  in  the  third  and  fourth 
years ;  in  the  fifth  and  sixth  years  the  store  deposited 
in  the  roots  has  become  sufficiently  rich  to  produce  in 
spring,  when  the  weather  is  warm,  three,  four,  and 
more  stems  as  thick  as  a  finger,  with  numerous  branches 
covered  with  leaves. 

A  comparative  examination  of  the  green  asparagus 
plant,  and  of  its  withering  stems  in  autumn,  seems  to 
indicate  that  at  the  end  of  the  period  of  vegetation  the 
remainder  of  the  dissolved  or  soluble  substances  fit  for 
future  use,  then  still  remaining  in  the  overground 
organs,  descend  to  the  root.  The  green  parts  of  the 
plant  are  comparatively  rich  in  nitrogen,  alkalis,  and 
phosphates,  whilst  in  the  withered  stems  these  sub- 
stances are  found  in  small  quantities  only.  The  seeds 


PERENNIAL   PLANTS.  31 

alone  retain  comparatively  large  proportions  of  phos- 
phated  earth  and  alkalis,  being  nothing  else  than  the 
excess  of  those  substances  which  the  roots  do  not  require 
for  the  next  year. 

The  underground  organs  of  perennial  plants  are  the 
economic  gatherers  of  all  the  vital  conditions  necessary 
for  certain  functions.  If  the  soil  will  allow,  they  always 
collect  more  than  they  give  out ;  they  never  spend  all 
they  receive.  These  plants  form  their  flowers  and  seeds 
when  the  roots  have  collected  a  certain  excess  of  phos- 
phates, which  may  be  given  up  without  endangering 
the  existence  of  the  plant.  An  abundant  supply  of 
nourishment,  by  means  of  manuring,  will  accelerate  the 
developement  of  the  plant  in  one  or  another  direction. 
Manuring  a  sward  with  ashes  will  draw  from  it  clover 
plants  ;  if  acid  phosphate  of  lime  is  employed,  French 
rye-grass  will  spring  up  in  thickly  serried  blades. 

In  all  perennial  plants,  the  underground  organs  are 
usually  very  much  greater  in  mass  and  extent  than 
those  of  annual  plants.  Whilst  the  roots  of  the  latter 
die  every  year,  the  former  preserve  theirs  in  a  state  of 
readiness  to  absorb  food  at  every  favourable  oppor- 
tunity. 

The  circle  from  which  a  perennial  plant  draws  its 
food  enlarges  from  year  to  year  ;  if  one  part  of  its  roots 
finds  little  nourishment  in  a  given  spot,  other  parts 
draw  their  supply  from  other  spots  richer  in  the  food 
required. 

Only  a  very  small  portion  of  the  plants  of  a  thickly 
covered  meadow  will  produce  stems :  the  far  greater 
part  will  develoj)e  only  tufts  of  leaves  ;  and  many  will 
for  years  be  confined  to  the  production  of  underground 
suckers. 

For  perennial  grass  and  meadow  plants,  the  produc- 
tion of  underground  suckers  is  of  the  highest  impor- 
tance, since  by  them  the  plant  is  furnished  with  nutri- 
ment at  a  time  when  a  scarcity  of  supply  would 
endanger  the  life  of  annual  plants. 

A  good  soil,  and  all  other  conditions  of  vegetable 
life,  will  of  course  exert  the  same  favourable  influence 


32  THE   PLANT. 

upon  perennial  as  on  annual  plants  ;  but  the  develope- 
nient  of  the  former  is  not  so  much  dependent  upon  acci- 
dental and  passing  states  of  the  weather,  as  is  the  case 
with  the  latter.  Unfavourable  conditions  will,  indeed, 
check  the  growth  of  a  perennial  plant,  but  only  for  a 
time,  until  a  favourable  change  ensues,  when  the  plant 
will  resume  growing ;  whereas  an  annual  plant,  under 
the  same  circumstances,  reaches  the  limits  of  its  exist- 
ence and  dies. 

The  permanence  of  vegetation  on  our  meadows,  and 
the  certainty  of  their  produce  under  varying  conditions 
of  soil  and  weather,  must  be  attributed  to  the  great 
number  of  plants  which  are  able  to  continue  for  a 
shorter  or  longer  period  at  a  low  stage  of  developement. 
While  the  one  species  of  plants  is  developed  above 
ground,  producing  flowers  and  seeds,  a  second  and  third 
species  gather  below  the  surface  the  conditions  for  a 
similar  future  growth.  The  one  vegetation  seems  to 
disappear,  to  make  room  for  another  and  a  third,  until 
for  itself  too  the  conditions  for  a  perfect  developement 
recur. 

The  woody  plants  grow  and  are  developed  in  a  man- 
ner quite  similar  to  the  asparagus  plant,  with  this  dif- 
ference, however,  that  they  do  not  lose  their  stem  when 
the  period  of  their  vegetation  comes  to  an  end.  An 
oak-sapling,  1-J-  foot  high,  was  found  to  have  a  root 
above  3  feet  long.  The  stem  and  the  root  serve  jointly 
as  a  magazine  for  storing  up  the  organi  sable  matter  to 
be  used  next  year  in  restoring  all  the  external  organs 
of  nutrition.  When  the  stems  of  lime  trees,  alders,  or 
willows  have  been  cut  down,  they  will,  if  lying  in  shady 
moist  places,  shoot  out  afresh,  often  after  the  lapse  of 
years,  and  produce  numerous  twigs  a  foot  long  or  more, 
covered  with  leaves. 

The  pauses  which  occur  in  the  seed-bearing  of  forest 
trees  are  similar  to  those  which  are  observed  in  most 
perennial  plants,  which,  when  growing  on  a  poor  soil, 
will  also  take  several  years  to  collect  the  conditions 
necessary  for  the  production  of  fruit  (Sendtner,  Eatze- 
burg). 


MINEKAL   MATTEES    IN   FALLEN    LEAVES.  33 

The  loss  of  inorganic  food-constituents,  which  the 
foliaceous  trees  suffer  by  the  fall  of  the  leaves,  is  trifling. 
When  the  leaves  have  attained  their  full  formation,  the 
cells  of  the  bark  receive  a  copious  supply  of  amylum, 
which  substance  completely  disappears  from  the  cells 
in  the  boss  of  the  leaf-stalk  (H.  Mohl).  Even  long  be- 
fore the  fall  of  the  leaves,  their  sap  is  considerably 
diminished,  while  the  bark  of  the  branches  is,  just 
at  that  time,  often  actually  overflowing  with  sap 
(H.  MOHL).  In  accordance  with  this  fact,  the  analysis 
of  the  ash  of  the  leaves  shows  that  the  amount  of  alkali 
and  phosphoric  acid  in  them  decreases  immediately 
before  the  fall ;  the  fallen  leaves  contain  such  trifling 
quantities  of  these  constituents,  in  comparison  to  their 
mass,  that  it  is  difficult  to  account  for  the  injurious 
consequences  arising  from  the  raking  up  and  removal 
of  the  fallen  leaves  in  woods.  (See  Appendix  A.) 

A  similar  reflux  of  the  assimilative  products  appears 
to  take  place  in  the  grasses ;  when  from  the  intense 
heat  of  summer  the  leaves  begin  to  decay,  chemical 
analysis  reveals  in  the  yellow  leaves  scarcely  any  traces 
of  nitrogen,  phosphates,  and  alkalis ;  and,  indeed,  ani- 
mals instinctively  turn  from  all  kinds  of  fallen  leaves, 
and  refuse  to  feed  on  them. 

In  annuals  and  biennials  the  organic  action  results 
in  the  production  of  fruit  and  seed,  after  which  the 
activity  of  the  root  comes  to  an  end  ;  in  perennials,  the 
production  of  seed  is  rather  an  accidental  condition  of 
their  permanent  existence. 

The  biennial  can  bestow  more  time  than  the  annual 
in  gathering  the  material  necessary  for  the  production 
of  seed  and  fruit,  which  closes  the  period  of  its  exist- 
ence ;  but  the  time  in  which  this  takes  place  depends 
upon  the  state  of  the  weather  and  the  nature  of  the  soil. 

The  annual  is  uniformly  developed  in  all  its  parts  ; 
the  food  daily  taken  up  is  expended  in  increasing  the 
overground  and  underground  organs,  which  meanwhile 
take  up  a  larger  amount  of  food  in  proportion  to  the 
increase  of  their  absorbent  surface.  With  the  growth 
of  the  plant,  the  conditions  of  increase  inherent  in  the 


34:  THE   PLANT. 

plant  itself  become  enlarged,  and  exert  their  influence 
in  proportion  as  the  external  conditions  are  favourable. 

The  developement  of  the  biennial  plants  cultivated 
for  their  roots  has  three  distinct  periods ;  in  the  first 
period  the  leaves  principally  are  formed  ;  in  the  second, 
the  roots,  in  which  are  stored  the  substances  needed  to 
produce  the  flower  and  fruit  during  the  third  period. 

A  series  of  experiments,  made  by  Anderson,  upon 
turnips,  affords  a  clear  viewpf  the  several  directions  in 
which  the  energy  of  a  biennial  plant  tends  at  different 
periods  of  its  growth.  ('  Journal  of  Agriculture  and 
Transactions  of  the  Highland  Society,'  No.  68,  69, 
new  series,  5.) 

These  experiments  were  made  to  ascertain  the  total 
produce  of  vegetable  substances  obtained  from  turnips 
on  one  acre  of  ground.  The  turnips  were  gathered  at 
four  different  stages  of  growth  ;  the  first  on  July  7,  the 
second,  on  August  11,  the  third,  on  September  1,  and 
the  fourth,  on  October  5.  The  following  table  shows 
the  weight  of  leaves  and  roots  in  pounds,  taken  up  at 
the  end  of  the  respective  stages,  and  calculated  upon 
one  acre  of  ground. 

Weight  of  leaves.  Weight  of  roots. 

I.     Harvest  after  32  days    ....          219  pounds  7'2  pounds 

II.  "          67    "        .     .     .     .     12,793       "  2,762 

III.  "          87    "        ....      19,200       "  14,400          " 

IV.  "        122    "        ....     11,208       "  36,792 

The  relative  quantities  of  leaves  and  roots  show  that 
in  the  first  half  of  the  time  of  vegetation,  sixty-seven 
days,  the  organic  labour  in  the  turnip  plant  is  princi- 
pally directed  to  the  production  and  developement  of 
the  external  organs. 

From  the  7th  July  to  the  llth  August,  a  period 
of  thirty-five  days,  we  find  the  increase  to  be  12,574 
pounds  in  the  leaves,  and  2,755  pounds  in  the  roots, 
which  gives  a  daily  increase  of 

Leaves.  Hoots. 

359  pounds.  |  78  pounds. 

In  this  stage,  accordingly,  the  production  of  leaves 
prevailed  over  that  of  roots  to  this  extent,  that  out  of 


GROWTH   OF   TURNIPS.  35 

eleven  parts  of  food  absorbed  by  the  plants,  nine  parts 
went  to  the  leaves  and  only  two  parts  to  the  roots. 

We  find  a  very  different  proportion  in  the  third 
stage  ;  for  during  twenty 'days  the  weight  of  the  leaves 
has  increased  by  6,507  pounds,  that  of  the  roots  by 
11,638  pounds,  which  gives  a  daily  increase  of 

Leaves.  Eoots. 

325  pounds.  |  582  pounds. 

During  this  third  stage  the  plants  take  up  daily  some- 
what more  than  double  the  amount  of  food  taken  up  on 
any  given  day  of  the  second  stage,  and  this  increase 
must  stand  in  proportion  to  the  daily  enlargement  of 
the  surface  of  the  roots  and  leaves ;  but  the  food 
absorbed  is  distributed  in  the  plant  in  a  very  different 
manner.  Of  twenty-five  parts  by  weight  of  food  ab- 
sorbed .and  assimilated,  nine  parts  only  remain  in  the 
leaves,  the  other  sixteen  parts  serve  to  increase  the  mass 
of  roots. 

In  exactly  the  same  ratio  as  the  leaves  approached 
the  limits  of  their  developement,  they  lost  the  power  of 
applying  to  their  further  growth  the  food  which  they 
had  absorbed,  and  which  now  transformed  into  organ- 
isable  matter  was  deposited  in  the  roots.  The  same 
nutritive  particles  which  went  to  form  leaves,  so  long 
as  the  mass  of  foliage  kept  on  increasing,  now  became 
constituent  portions  of  the  root. 

This  migration  of  the  constituents  of  the  leaves  and 
transformation  into  constituents  of  the  root  appear  to  be 
most  clearly  shown  in  the  fourth  stage.  The  total 
weight  of  leaves,  which  on  the  1st  September  still 
amounted  to  19,200  pounds,  had  by  the  5th  October, 
or  within  the  space  of  thirty-five  days,  decreased  by 
7,992  pounds,  that  is  228  pounds  a  day ;  in  other 
words,  out  of  every  thirty-four  leaves  ten  had  withered, 
while  the  roots  had  increased  by  22,392  pounds,  or  640 
pounds  a  day — a  daily  increase  much  more  considerable 
than  during  the  third  stage. 

It  is  evident  that  with  the  advance  of  autumn,  with 
the  lower  temperature  and  diminished  action  of  .sun- 


36 


THE   PLANT. 


light,  the  organic  energy  of  the  leaves  decreased,  and 
more  than  a  third  of  the  organisable  matter  collected  in 
them  descended  to  the  roots,  to  be  stored  up  for  future 
use. 

If  we  compare  the  quantities  of  nitrogen,  phosphoric 
acid,  potash,  common  salt,  and  sulphuric  acid,  absorbed 
during  the  last  ninety  days  by  the  turnips  growing  on 
one  acre  of  ground,  we  find  from  Anderson's  experi- 
ments that  the  daily  amount  was  as  follows  : — 

Absorbed  by  the  entire  plant  in  a  day. 


Total  increase. 

Second  stage. 

Third  stage. 

Fourth  stage. 

In  substance                 .  .     .  . 

437 

907 

Pounds. 
417 

Nitrogen  

115 

0-695 

1-21 

Phosphoric  acid                   . 

0-994 

1-10 

1-25 

Potash    

1-41 

4-04 

"  3-07 

Sulphuric  acid              . 

1-12 

1-57 

1*52 

Salt          

0'84 

1-98 

I'll 

Daily  increase  of  roots  in  the  fourth  stage  of  growth. 


Phosphoric 
acid. 

Potash. 

Sulphuric 
acid. 

Salt. 

Supplied  by  the  soil  .  . 
"      leaves 

1-25 
0-41 

3-07 
1-56 

1-52 
0-51 

1-10 
0-53 

1-66 

4-63 

2-03 

1-63 

These  figures  show  that  the  quantity  of  phosphoric 
acid  taken  up  daily  by  the  turnip  plants  growing  on 
one  acre  of  ground  increases  from  the  commencement 
of  the  second  to  the  end  of  the  fourth  stage  of  growth, 
that  is  in  ninety  days  from  0*924  to  1*25  pound  a-day, 
which  reckoned  from  one  day  to  another  makes  the 
trifling  difference  of  0*0037  pound  a-day. 

Anderson  suspects  that  his  estimate  of  the  nitrogen 
in  the  leaves  during  the  third  stage  was  not  quite  cor- 
rect, and  that  it  fell  below  the  actual  amount.  If  we 


PHOSPHORIC    ACID   AND   POTASH   IN   GROWING    TUKNIPS.    37 

add  together  the  quantities  of  nitrogen  absorbed  in  the 
last  two  stages,  fifty-five  days,  we  find  a  daily  average 
of  1'02  pound  of  nitrogen,  which  is  very  nearly  the,  same 
as  in  the  preceding  stage  of  growth. 

The  quantity  of  potash  increased  from  the  llth  Au- 
gust till  the  1st  September,  in  a  somewhat  higher  ratio 
than  the  amount  of  vegetable  substance  produced. 
From  the  1st  September  till  the  5th  October  the  in- 
crease of  the  roots  was  nearly  double  what  it  had  been 
in  the  preceding  stage,  but  this  is  explained  by  the 
migration  of  the  potash  compounds  from  the  leaves  to 
the  roots.  It  is  evident  that  the  increase  of  potash  has 
a  certain  connection  with  the  formation  of  sugar  and 
the  other  non-nitrogenous  constituents  of  the  roots,  but 
no  definite  proportion  can  be  established  between  them. 
The  absorption  of  sulphuric  acid  increased  uniformly  in 
the  three  last  stages  ;  that  of  salt  was  a  little  greater  in 
the  third  than  in  the  second  and  fourth  stages. 

Without  wishing  to  indicate  the  exact  part  per- 
formed in  the  process  of  vegetation  by  these  various 
mineral  substances,  as  also  by  lime,  magnesia,  and  iron, 
we  remark  that,  except  in  the  case  of  potash,  the  absorp- 
tion of  them  was  evidently  uniform  from  day  to  day, 
yet  showing  every  day  a  trifling  increase  corresponding 
to  the  daily  increase  of  the  food-absorbent  surface  up  to 
the  fourth  stage  of  growth. 

The  smallest  increase  was  seen  in  phosphoric  acid 
and  nitrogen,  both  equally  necessary  for  the  formative 
processes  going  on  in  the  turnip  plant ;  and  it  is  mani- 
fest that  they  must  have  served  to  bring  into  operation 
some  more  powerful  agency,  whose  effects  are  revealed 
in  the  production  and  augmentation  of  the  non-nitro- 
genous constituents. 

If  we  take  the  quantity  of  mineral  substances  ab- 
sorbed as  the  measure  of  their  importance  for  the 
organic  operations  going  forward  in  the  plant,  we  must 
assign  to  sulphuric  acid  and  common  salt  an  influence 
equal  to  that  of  any  of  the  others. 

Looking  at  the  qualities  of  mineral  constituents  sev- 
erally taken  up  by  the  different  parts  of  the  plant  in  the 


38  THE   PLANT. 

various  stages  of  growth,  we  observe  the  greatest  dis- 
parities. In  the  second  stage,  a  quantity  of  potash, 
amounting  in  the. aggregate  to  49 -29  pounds,  was  ab- 
sorbed in  35  days  ;  and  of  this,  the  roots  were  found  to 
contain  8 '02  pounds,  equal  to  one-sixth — the  leaves 
41*27  pounds,  equal  to  five-sixths.  The  same  propor- 
tion— namely,  about  five  to  one — was  found  to  exist 
between  the  weight  of  the  leaves  produced,  and  that  of 
the  roots. 

In  the  third  stage,  the  weight  of  the  roots  produced 
exceeded  that  of  tire  leaves ;  and  of  the  80  pounds  of 
potash  absorbed  by  the  plants,  34  pounds,  or  more  than 
one-third,  remained  in  the  roots.  The  same  was  found 
to  be  the  case  with  phosphoric  acid,  and  the  other 
mineral  constituents ;  that  is  to  say,  they  were  found 
distributed  in  varying  proportions,  corresponding  to  the 
growth  and  increase  of  the  mass  of  the  overground  and 
underground  organs  of  the  turnip  plants,  which,  in  the 
various  stages,  are  likewise  not  uniform. 

If  we  regard  the  mere  increase  of  the  leaves  and 
roots  in  mineral  substances,  without  reference  to  the 
total  amount  of  them  absorbed  by  the  entire  plant,  it 
appears  to  be  most  irregular,  and  to  proceed  by  '  fits 
and  starts.'  The  plant  receives  every  day  nearly  the 
same  quantity  of  phosphoric  acid,  nitrogen,  salt,  and 
sulphuric  acid,  which  are  distributed  in  the  several 
parts  of  the  plant,  leaves,  or  roots,  where  they  are  re- 
quired for  use.  The  chief  difference  observable  is  in 
the  increase  of  potash,  which  in  the  third  stage  is  out 
of  all  proportion  greater  than  that  of  the  other  mineral 
constituents. 

It  is  highly  probable  that  from  the  raw  material — 
i.  e.  the  carbonic  acid,  water,  ammonia,  phosphoric  acid, 
sulphuric  acid,  with  the  cooperation  of  the  alkalis, 
earths,  &c. — the  chemical  process  engenders  in.  the 
plant  simply  a  nitrogenous  and  sulphureous  substance, 
belonging  to  the  albumen  group,  and  only  one  non- 
nitrogenous  substance,  belonging  to  the  group  of  hydro- 
carbons. The  former  retains  its  character  during 
the  period  of  vegetation;  while  the  non-nitrogenous 


NITROGENOUS    SUBSTANCES    IN   TUENIPS.  39 

substance  is  converted  into  a  tasteless,  gum-like  body, 
or  into  cellulose,  or  sugar — becoming  a  constituent  of 
the  leaves  or  of  the  roots,  according  as  the  organic 
energy  preponderates  in  the  overground  or  under- 
ground organs. 

If  there  is  a  relation  between  the  phosphoric  acid 
and  the  production  of  the  nitrogenous  constituents,  the 
soil  must  contain,  in  its  parts,  definite  proportions  of 
both  substances ;  and  for  the  cultivation  of  turnips,  the 
upper  layers  must  necessarily  be  much  richer  in  phos- 
phates than  the  lower.  For  in  the  first  half  of  the 
period  for  vegetation,  the  branching  of  the  roots  is  much 
less  extensive  than  at  a  later  period,  and  the  root  is  in 
contact  with  a  much  smaller  bulk  of  earth  than  after- 
wards ;  hence,  if  the  root  is  to  draw  from  this  smaller 
bulk  the  same  amount  of  nourishment  as  from  the 
larger,  the  former  must  contain  more  of  it,  in  propor- 
tion as  the  absorbent  root-surface  is  smaller. 

The  ash  of  all  plants  in  whose  organism  large  quan- 
tities of  amylum,  gum,  and  sugar  are  produced,  is  dis- 
tinguished from  the  ash  of  other  plants  by  the  prepon- 
derance of  potash  ;  now,  if  the  potash  in  the  sap  of  the 
turnip  plant  formed  a  necessary  agent  in  the  formation 
of  sugar  and  the  other  non-nitrogenous  constituents,  the 
quantity  of  that  mineral  matter  absorbed  in  the  third 
and  fourth  stages  of  growth  is  easily  explained — because 
the  formation  of  the  non-nitrogenous  constituents  of  the 
root  was  more  active  in  these  than  in  the  former  stages. 

That  the  production  of  the  combustible  constituents 
— the  conversion  of  the  carbonic  acid  and  ammonia  into 
non-nitrogenous  and  azotised  substances — stands  in  a 
definite  relation  of  dependence  to  the  incombustible 
matter  found  in  the  ash,  is  an  opinion  which  no  longer 
requires  special  proof  to  support  it.  But  the  depend- 
ence is  mutual.  To  say  that  the  reason  why  the 
azotised  or  non-nitrogenous  products  are  formed  in 
large  proportion  is  because  the  plant  has  taken  up  more 
phosphoric  acid  or  potash,  is  just  as  correct  as  to  assert 
that  the  plant  takes  up  more  phosphoric  acid  or  potash 
because  the  other  conditions  required  for  the  production 


4:0  THE   PLANT. 

of  azotised  or  non-nitrogenous  substances  are  found  com- 
bined in  its  organism. 

To  enable  a  plant  to  attain  its  maximum  of  growth, 
the  soil  must  at  all  times  yield,  in  an  available  form, 
the  whole  quantity  of  each  of  its  constituents ;  and,  on 
the  other  hand,  the  cosmic  conditions — heat,  moisture, 
and  sunlight — must  cooperate  to  transmute  the  absorbed 
substances  into  the  organs  of  the  plant.  If  the  sub- 
stances that  have  passed  from  the  soil  into  the  plant 
cannot  be  turned  to  account,  from  the  want  of  this  co- 
operation, no  fresh  substances  are  absorbed;  in  un- 
favourable weather,  the  plant  does  not  grow.  No  more 
does  it  grow,  even  though  the  outward  conditions  are 
favourable,  if  the  soil  contains  no  proper  nourishment. 

In  the  second  half  of  the  period  of  developement,  the 
roots  of  the  turnip  plant,  having  penetrated  through  the 
arable  surface  deep  into  the  subsoil,  absorb  more  potash 
than  in  the  preceding  stage.  If  we  suppose  that  the 
absorbing  spongioles  of  the  root  reach  a  stratum  of  soil 
poorer  in  potash  than  the  upper  layer,  or  not  sufficiently 
rich  in  that  material  to  yield  a  daily  supply  commensu- 
rate with  the  requirements  of  the  plant,  at  first,  indeed, 
the  plant  may  appear  to  grow  luxuriantly;  yet  the 
prospect  of  an  abundant  crop  will  be  small,  if  the  sup- 
ply of  the  raw  material  is  constantly  decreasing,  instead 
of  enlarging  with  the  increased  size  of  the  organs. 

In  the  economy  of  the  turnip,  the  root  receives  dur- 
ing the  last  month  of  vegetation  nearly  one-half  of  all 
the  movable  constituents  of  the  leaves ;  and  this  consti- 
tutes, after  the  completion  of  its  first  year's  period  of 
vegetation,  a  store  of  organisable  matter  for  future  use. 

During  the  spring  of  the  following  year  the  root 
begins  to  shoot,  putting  forth  a  slight  leafy  top,  and  a 
flower-stalk  several  feet  high ;  with  the  developement 
and  maturing  of  the  seed,  the  plant  dies.  The  chief 
bulk  of  the  food  stored  up  in  the  root  is  applied,  in  the 
second  year  or  third  period,  in  quite  a  different  direc- 
tion ;  though,  beyond  the  mere  supply  of  water,  the  soil 
seems  to  take  no  part  in  this  new  act  of  life. 

All  monocarpous  plants— that  is,  all  plants  which 


SUMMER   PLANTS.  41 

flower  and  produce  seed  but  once — present,  like  the 
turnip  plant,  distinct  periods  of  life,  as  regards  the 
direction  of  organic  activity  in  them.  In  the  first,  the 
plant  produces  the  organisable  matter  required  in  the 
succeeding  period ;  in  the  latter,  that  which  is  required 
for  the  final  functions  of  life.  But  these  materials  are 
not  always  stored  up  in  the  root,  as  is  the  case  in  the 
turnip ;  in  the  sago-palm  they  fill  the  stem ;  in  the 
aloe  (Agave)  they  collect  in  the  thick  fleshy  leaves. 

The  production  of  seed  is,  with  many  of  these  plants, 
much  less  dependent  upon  any  fixed  period  of  time, 
than  upon  the  store  of  organisable  matter  collected  in 
them  in  the  time  preceding.  Favourable  climatic  con- 
ditions or  propitious  weather  will  hasten,  while  unfa- 
vourable cosmic  conditions  will  retard,  its  production. 

The  so-called  summer-plants  are  monocarps  which 
are  able  to  gather  in  a  few  months  the  conditions  re- 
quired for  the  production  of  seed.  The  oat-plant  grows 
to  maturity  and  bears  ripe  seed  in  ninety  days;  the 
turnip-rape  only  in  the  second  year  of  its  existence ; 
the  sago-palm  in  sixteen  to  eighteen  years  ;  the  aloe  in 
thirty  to  forty,  often  not  till  100  years.  (See  Appen- 
dix B.) 

In  many  perennial  plants,  the  outer  part  dies  every 
year,  while  the  root  lives  on.  In  the  monocarpous 
plants,  the  root  dies  with  the  production  of  the  seed. 
In  these  the  production  of  seed  is  an  indispensable, 
in  the  perennial  plants  more  of  an  accidental,  condition 
of  continued  existence. 

The  economy  of  plants  is  regulated  by  laws  which 
manifest  their  operation  in  the  peculiar  faculty  of  cer- 
tain organs  to  store  up  food  for  future  use ;  so  that  all 
the  external  causes  which  seem  to  hinder  their  develope- 
ment,  actually  contribute  in  the  end  to  insure  their 
continued  existence,  i.~e.  their  propagation. 

The  contents  of  the  roots  .in  perennial  grasses  and 
asparagus,  may,  in  the  different  periods  of  the  life  of 
these  plants,  be  compared  to  the  farinaceous  body  or 
albumen  in  the  grain  of  cereals ;  with  this  difference, 
however,  that  the  skin  does  not  become  empty  as  is  the 


42  THE   PLANT. 

case  with  the  latter  on  germination,  but  is  always  re- 
filled and  keeps  increasing  in  size.  The  perennial  plant 
always  receives  more  than  it  expends;  whereas  the 
monocarpous  plant  spends  its  whole  store  in  forming 
fruit. 

The  fact  that  the  roots  of  the  turnip,  in  autumn, 
grow  at  the  cost  of  the  constituents  of  the  leaves, 
readily  explains  the  influence  which  the  removal  of 
leaves  will  exercise  upon  the  crop  at  different  stages  of 
growth.  The  removal  of  a  few  leaves  in  August  makes 
no  great  difference  to  the  root,  while  the  removal  of 
leaves  at  the  end  of  September  causes  the  greatest  dam- 
age to  the  root-crop.  Metzler,  who  made  very  accurate 
comparative  experiments  upon  this  point,  found  that  an 
early  cutting  of  the  leaves  reduced  the  turnip  crop  by 
7  per  cent,  only,  while  a  late,  or  a  second  cutting,  re- 
duced it  by  as  much  as  36  per  cent. 

If,  in  the  first  year,  instead  of  the  turnips  being  re- 
moved from  the  field  at  harvest,  the  tops  were  merely 
cut  off  and  the  roots  were  left  and  ploughed  in,  the  field 
would,  on  the  whole,  sustain  a  loss  of  soil  constituents  ; 
still  the  roots  in  the  soil  would  retain  the  greater  por- 
tion of  them.  A  very  different  relation  would  arise,  if 
at  the  end  of  the  second  year  of  vegetation  the  turnip 
tops  were  cut  off,  and  the  stem  were  removed  together 
with  the  seed.  For,  at  the  end  of  the  first  year,  the 
root  would  still  retain  the  far  larger  portion  of  the 
azotised  and  also  of  the  incombustible  constituents, 
which  would  thus  be  left  in  the  soil ;  but  in  the  second 
year  these  materials  would  be  carried  into  the  over- 
ground part  of  the  plant,  and  there  be  used  for  the 
production  of  the  stem  and  the  seed;  hence,  the  re- 
moval of  the  latter  would  of  course  make  the  soil  poorer, 
even  though  the  roots  were  now  left  in  it.  Before  the 
shooting  and  flowering,  the  root  was  rich  in  soil  con- 
stituents ;  after  the  production  of  seed,  its  store  of  them 
is  exhausted.  If  the  plant  is  cut  off  and  the  root  left 
in  the  ground,  before  flowering,  the  soil  retains  the  far 
greater  portion  of  the  nutritive  matter  which  it  had 
given  to  the  plant ;  on  the  contrary,  after  flowering  and 


THE   TOBACCO   PLANT.  43 

the  production  of  seed,  the  root  retains  only  a  small 
residue  of  these  constituents,  and  the  soil  is  correspond- 
ingly exhausted  of  them. 

As  it  is  with  the  turnip,  so  is  it  with  culmiferous 
plants.  If  they  are  cut  off  before  flowering,  a  consider- 
able portion  of  the  nutritive  substances  stored  up  in 
them  remains  in  the  root,  which  the  soil  of  course  loses, 
if  the  overground  plant  is  removed  after  the  ripening 
of  the  seed. 

The  experience  derived  from  the  cultivation  of 
tobacco  gives  a  clear  view  of  the  processes  in  the  devel- 
opement  of  an  annual  leafy  plant. 

In  the  tobacco  plant  the  overground  and  the  under- 
ground parts  grow  with  perfect  equality ;  the  root  gains 
in  extent,  in  the  same  proportion  as  the  stem  lengthens 
and  the  leaves  increase  in  number  and  size.  There  is 
no  appearance  of  sudden  changes  in  the  direction  of  or- 
ganic activity,  no  shooting,  but  the  phases  of  life  in  the 
plant  follow  in  steady  continuous  progression.  Even 
while  the  top  of  the  stem  bears  ripe  seeds,  and  the 
lower  leaves  have  withered,  the  side  shoots  of  the  plant 
are  often  still  putting  forth  flower-buds,  the  seeds  of 
which  will  ripen  at  a  much  later  period. 

The  tobacco  plant  is  remarkable  for  producing  in  its 
organism  two  nitrogenous  compounds,  of  which  the  one, 
nicotine,  contains  neither  sulphur  nor  oxygen ;  while 
the  other,  albumen,  is  identical  with  the  sulphureous 
and  oxygenised  constituents  of  the  cereals  and  other 
alimentary  plants. 

The  commercial  value  of  tobacco  leaves  is  in  an  in- 
verse ratio  to  the  amount  of  albumen  which  they  con- 
tain, that  sort  of  tobacco  being  most  highly  esteemed 
by  smokers  which  contains  the  least  albumen ;  for  the 
latter  ingredient,  in  the  burning  of  the  dry  leaves,  emits 
on  carbonisation  a  most  disagreeable  smell  of  burnt 
horn  shavings.  The  leaves  rich  in  albumen  contain,  as 
a  rule,  more  nicotine  than  those  which  are  poor  in  albu- 
men ;  they  give  the  strongest  kinds  of  tobacco,  many  of 
which  cannot  be  smoked  unmixed. 

The  tobacco  leaves  cultivated  in  France  and  Ger- 


44  THE  PLANT. 

many  are  manufactured  either  into  smoking  tobacco  or 
into  snuff.  For  the  fabrication  of  snuff,  leaves  which 
are  rich  in  albumen  and  nicotine  are  preferred  to  those 
containing  a  smaller  amount  of  those  ingredients.  The 
leaves  intended  for  snuff  are,  either  when  still  entire  or 
after  being  ground  to  powder,  subjected  to  a  kind  of 
fermentation,  which  takes  place  pretty  speedily,  with 
evolution  of  heat,  if  they  are  kept  moistened  with 
water.  From  the  putrefaction  of  the  albumen  there 
arises  a  considerable  quantity  of  ammonia,  which  is  a 
principal  ingredient  of  German  snuff,  and  is  also  occa- 
sionally increased  by  the  manufacturers,  by  moistening 
with  carbonate  of  ammonia  or  caustic  ammonia,  to  suit 
the  taste  of  consumers. 

The  leaves  intended  for  smoking  are  also  improved 
in  quality  by  a  slight  process  of  fermentation,  which 
serves  to  diminish  the  quantity  of  albumen  in  them. 

These  preliminary  remarks  will  help  to  explain  the 
different  methods  of  cultivating  tobacco. 

The  size  of  the  leaf  in  length  and  breadth,  its  light 
or  dark  colour,  the  height  of  the  stem,  the  amount  of 
produce,  a-nd  the  greater  or  less  proportion  of  albumen 
and  nicotine,  all  depend  very  essentially  upon  the 
manuring  of  the  plant. 

The  plant  succeeds  best,  in  Europe,  on  light,  sandy, 
humose,  loamy,  or  marly  soils.  The  strongest  kinds, 
richest  in  albumen  and  nicotine,  are  grown  on  virgin 
land,  and  on  heavy  clay  soil  manured  with  bone-dust, 
shavings  and  clippings  of  horns  and  claws,  blood, 
bristles,  human  excrements,  oilcake,  and  liquid  manure. 

In  Havannah,  tobacco  is  grown  on  virgin  soil,  on 
cleared  forest  lands,  which  are  often  burnt  first,  as  is 
done  in  Virginia.  The  best  qualities  (the  poorest  in 
albumen)  are  yielded  in  the  third  year  of  cultiva- 
tion. 

From  this  it  would  appear,  that  animal  manure 
abounding  in  nitrogen  (ammonia)  favours  the  produc- 
tion of  nitrogenous  constituents;  but  the  soil,  on  the 
other  hand,  which  is  poor  in  ammonia,  and  probably 


CULTIVATION   OF   TOBACCO.  45 

contains  the  nitrogen  in  the  form  of  nitric  acid,  pro- 
duces leaves  containing  much  less  albumen  and  nico- 
tine. 

The  effect  of  removing  the  tobacco  plant  from  the 
rearing  beds  to  the  field  is  very  striking.  Transplanted 
into  the  new  soil,  the  young  tobacco  plant  proceeds  in 
the  first  instance,  like  seed  in  the  process  of  germina- 
tion, to  produce  roots;  the  leaves  already  formed 
wither  on  transplantation,  and  their  movable  constitu- 
ents, together  with  the  store  of  organisable  matter  col- 
lected in  the  roots,  are  applied  to  the  production  of 
numerous  branch  radicles.  A  second  transplantation 
has  a  still  more  favourable  effect  upon  the  underground 
organs  of  absorption. 

As  the  direction  of  the  organic  operations  in  sum- 
mer-plants is  entirely  turned  to  the  formation  of  seed, 
and  as  this  consumes  the  materials  which  give  activity 
to  the  roots  and  leaves,  the  tobacco  planter  breaks  out, 
when  the  plant  has  put  forth  six  to  ten  leaves,  the  heart 
of  the  middle  stem,  on  which  the  flowers  and  seed  cap- 
sules grow.  Stripped  thus  of  the  crown,  the  whole 
vigour  of  the  plant  is  now  directed  to  the  buds  between 
the  leaves  and  stem,  and  these  put  forth  side-shoots 
which  are  treated  like  the  principal  stem,  that  is  to  say, 
they  are  either  broken  away,  or  simply  cracked  by 
twisting.  Thus  the  leaves  retain  the  organisable  matter 
subsequently  produced,  and  increase  in  mass  and  size, 
while  the  amount  of  water  in  them  diminishes.  By  the 
middle  of  September,  the  leaves  lose  their  green  colour 
and  are  spotted  with  yellow  blotches,  imparting  a  mar- 
bled look ;  they  become  parchment-like,  feel  dry  to  the 
touch,  get  flaccid,  with  the  ends  drooping  to  the  ground, 
and,  when  arrived  at  fall  maturity,  are  viscous,  clammy, 
and  readily  conie  off  the  stem. 

This  treatment  is  variously  modified,  according  to 
the  several  varieties  of  tobacco,  and  the  different  coun- 
tries in  which  it  is  grown.  The  so-called  common  Eng- 
lish tobacco,  which  is  particularly  rich  in  nicotine,  is 
often  allowed  by  planters  to  run  to  seed,  in  order  to 


4:6  THE   PLANT. 

effect  a  separation  of  the  nitrogenous  constituents,  the 
albumen  forsaking  the  leaves  and  lodging  in  the  seed. 

In  the  young  shoots,  buds,  and  generally  in  all 
parts  in  which  the  production  of  cells  is  most  actively 
carried  on,  the  sulphureous  and  nitrogenous  constitu- 
ents (albumen)  accumulate,  and  thus  the  younger  leaves 
are  always  richer  in  these  substances  than  the  older. 
The  leaves  nearest  the  ground  (sand-leaves)  give  a 
milder,  the  upper  leaves  a  stronger  tobacco.  In  those 
varieties  which  are  not  particularly  rich  in  nicotine  and 
albumen,  the  sand-leaves  are  of  much  less  value  than 
the  upper  leaves.  A  mild  tobacco  always  means  a 
tobacco  poor  in  narcotic  constituents. 

The  course  pursued  by  the  European  tobacco  plant- 
er, who  lays  a  superabundance  of  animal  manure  upon 
his  fields,  is  the  exact  reverse  of  that  adopted  by  the 
American  planter,  who  cultivates  his  plants  upon  a 
field  that  has  never  been  manured.  The  one  seeks  to 
reduce  or  dilute  the  narcotic,  sulphureous,  and  nitro- 
genous constituents  of  the  leaves  ;  the  other  to  concen- 
trate them.  Accordingly,  the  American  planter  breaks 
the  lower  leaves  in  their  full  vigour,  when  the  plant 
has  attained  to  half-growth ;  the  European  planter  at- 
taches the  greatest  value  to  the  fully-developed  upper 
leaves. 

As  the  tobacco  plant,  like  all  annuals,  only^  yields 
up  its  whole  store  of  organisable  matter  at  the  ripening 
of  the  seeds,  the  stem  does  not  die  after  the  loss  of  the 
leaves ;  but  the  materials  still  remaining  in  it  and  in 
the  roots  cause  the  stem  to  send  forth  fresh  shoots,  and 
frequently  even  leaves,  though  small-sized  ones.  In  the 
"West  Indies,  Maryland,  and  Virginia,  before  the  gather- 
ing of  the  leaves,  the  stems  are  notched  immediately 
above  the  ground,  so  that  they  lean  over  without  being 
severed  from  the  root.  In  warm  weather,  the  water  in 
the  leaves  evaporates,  and  a  motion  of  the  sap  ensues 
from  the  stems  and  roots  towards  the  leaves,  in  which 
the  sap  is  thus  concentrated  as  the  plant  withers.  The 
tobacco  planters  on  the  Rhine  have  found  that  a  supe- 


MODE   OF   GROWTH    OF   WINTER-WHEAT.  47 

rior  tobacco,  poorer  in  albumen  and  nicotine,  is  pro- 
duced if,  instead  of  breaking  the  leaves  oif  in  the  field, 
the  plant  with  the  leaves  on  it  is  cut  down  just  above 
the  ground,  and  hung  up  to  dry  with  the  top  down- 
wards. The  stem  will,  under  these  circumstances,  con- 
tinue to  vegetate  for  a  time,  sending  forth  small  shoots 
which  gradually  turn  in  an  upward  direction  and  put 
forth  flower-buds.  In  these  flower-buds  the  sulphureous 
and  nitrogenous  constituents  are  collected  from  the 
leaves,  which  lose  these  ingredients  in  the  same  propor- 
tion, and  are  thereby  improved  in  quality. 

Of  the  plants  cultivated  for  the  sake  of  their  seed, 
wheat  holds  the  chief  place. 

Winter-wheat  is  in  its  developement  extremely  like 
a  biennial  plant.  In  the  biennial  turnip  we  see  that 
with  the  first  leaves  a  corresponding  number  of  root- 
fibres  are  produced  ;  and  that  after  the  formation  of  the 
leaf-top,  the  root  begins  to  expand  greatly  in  size  and 
extent,  immediately  after  which  the  flower  and  seed- 
stalk  shoots  forth. 

Yery  soon  after  winter-wheat  is  sown,  the  young 
plant  puts  forth  the  first  leaves,  which  in  the  course  of 
winter  and  the  early  months  of  spring  increase  to  a 
tuft ;  to  all  appearance  the  vegetation  of  the  plant 
seems  to  cease  for  weeks  and  months.  When  warm 
weather  comes,  the  plant  puts  forth  a  soft  stem,  several 
feet  high,  furnished  with  leaves,  and  bearing  at  the  top 
an  ear  set  with  flower-buds  in  which,  after  flowering, 
the  seeds  are  formed.  As  the  seed  is  developed,  the 
leaves  from  the  bottom  upwards  turn  yellow,  and  die 
with  the  stem  as  the  seed  ripens. 

It  cannot  be  doubted  that  while  the  growth  of  the 
plant  appears  to  have  ceased  before  the  time  of  shoot- 
ing, the  over  and  under  ground  organs  are  in  constant 
activity  ;  food  is  incessantly  absorbed,  which,  however, 
is  but  partially  employed  to  increase  the  mass  of  leaves, 
but  not  to  form  the  stem.  There  is,  therefore,  every 
reason  to  believe  that  the  far  larger  portion  of  the  or- 
ganisable  matter  produced  in  the  leaves  during  this 


48  THE    PLAtfT. 

period  goes  to  the  roots,  and  that  this  store  is  after- 
wards applied  to  the  formation  of  the  stalk.  On  the 
approach  of  warmer  weather  all  the  operations  of  life  in 
cereal  plants  are  quickened,  and  the  quantity  of  food 
daily  absorbed  and  worked  up  increases  with  the  extent 
of  the  absorbing  and  elaborating  organs.  In  spring 
many  of  the  older  leaves  and  of  the  root-fibres  die  in 
the  portions  of  the  soil  exhausted  by  them ;  the  root- 
tops  send  forth  new  buds,  and  with  every  new  bud  new 
rootlets,  until  the  stalk-joints  have  attained  a  certain 
length.  From  this  time  forward  to  the  end  of  the  pe- 
riod of  vegetation,  both  the  food  absorbed  by  the  plant, 
and  the  movable  part  of  the  materials  formed  in  the 
leaves,  stem,  and  root,  go  to  form  flowers  and  seeds. 

The  observations  of  Schubart  show  that  the  roots  of 
cereal  plants,  in  the  first  period  of  vegetation,  increase 
much  more  than  the  leaves.  Schubart  found  that  rye 
plants,  which,  six  weeks  after  sowing,  presented  leaves 
5  inches  long,  had  meanwhile  produced  roots  2  feet  in 
length. 

The  vigour  with  which  cereal  plants  send  forth  their 
stalks  and  side-shoots  corresponds  to  the  developement 
of  the  root.  Schubart  found  as  many  as  eleven  side- 
shoots  in  rye  plants,  with  roots  3  to  4  feet  long ;  in 
others,  where  the  roots  measured  If  to  2J  feet,  he  found 
only  one  or  two ;  and  in  some,  where  the  roots  were 
but  1^  foot,  no  side-shoots  at  all. 

The  action  of  a  low  temperature  in  autumn  and  win- 
ter, which  puts  a  certain  limit  to  the  activity  of  the 
outer  organs,  without  altogether  suppressing  it,  is  essen- 
tial to  the  vigorous  thriving  of  winter  corn.  It  is  a 
most  favourable  condition  for  future  developement,  if 
the  temperature  of  the  air  is  below  that  of  the  soil,  so 
as  to  retard  for  several  months  the  developement  of  the 
outer  plant. 

Hence  a  very  mild  autumn  or  winter  operates  un- 
favourably upon  the  future  crop,  as  the  higher  temper- 
ature encourages  the  developement  of  the  principal 
stalk  before  the  proper  time,  which  shoots  up  thin,  and 


DIFFERENT   STAGES    OF   GROWTH   OF   THE   OAT-PLANT.     49 

consumes  the  food  which  should  have  served  to  form 
buds  and  new  roots,  or  to  increase  the  store  of  organisa- 
ble  matter  in  the  roots.  Thus  stunted  in  its  develope- 
ment,  the  root  supplies  less  food  to  the  plant  in  spring, 
as  it  takes  up  and  gives  out  less  in  proportion  to  its 
smaller  absorbent  surface  and  more  limited  supply 
stored  up  in  it ;  and  it  retains  the  same  feeble  character 
in  the  succeeding  periods  of  vegetation.  The  agricul- 
turist endeavours  to  meet  the  difficulty  by  grazing  down 
or  cutting  these  feeble  plants ;  the  formation  of  buds 
and  roots  hereupon  begins  anew,  and  if  the  external 
conditions  are  favourable,  and  the  plant  has  time  to 
fill  the  root  with  a  fresh  store  of  organisable  matter,  the 
normal  conditions  of  growth  are,  in  the  agricultural 
sense,  restored.  Summer  corn  maintains,  in  the  several 
periods  of  its  developement,  the  same  character  as  win- 
ter corn  ;  only  these  periods  are  of  much  shorter  dura- 
tion. 

Ahrend's  study  of  the  oat-plant  in  its  several  stages 
of  growth  is  instructive  in  this  respect.  He  determined 
the  increase  in  combustible  and  incombustible  constitu- 
ents during  the  following  periods  :  from  germination  to 
the  beginning  of  shooting  (end  of  the  first  stage,  18th 
June) ;  from  this  time  to  shortly  before  the  end  of 
shooting  (second  stage,  30th  June) ;  immediately  after 
flowering  (third  stage,  10th  July) ;  the  commencement 
of  ripening  (fourth  stage,  21st  July)  ;  finally,  to  perfect 
maturity  (fifth  stage,  31st  July).  On  the  18th  June 
the  plants  were  on  an  average*  31  centimeters  high  (1J 
inch),  the  three  lower  leaves  were  nearly  expanded,  the 
two  upper  leaves  were  still  folded  up.  Of  the  stalk- 
joints  the  three  lower  alone  had  an  appreciable  length 
(1,  2,  and  3  centimeters),  the  three  upper  had  but  a  "ru- 
dimentary existence.  Twelve  days  after  (on  the  30th 
June)  the  plant  had  attained  double  the  height  (63  cen- 
timeters) ;  and  ten  days  after  this  again,  on  the  10th 
July,  after  flowering,  it  had  reached  84  centimeters. 

1,000  plants  respectively  produce  in  grammes  : — 
3 


50 


THE    PLANT. 


Constituents 


Combustible.  . 
Incombustible. 


Examined  on 

18th  June. 
I.  stage. 

In  49  days, 
before 
shooting. 

30th  June. 
11.   stage. 

In  12  days, 
stalks  full 
grown. 

10th  July. 
III.  stage. 

In  10  days, 
flowering. 

21st  July. 
IV.  stage. 

In  11  days, 
formation  of 
seed. 

81st  July 
V.  stage. 

In  11  days, 
ripening. 

Grammes. 
419 
36-6 

Grammes. 
873 
33-48 

Grammes. 
475 
30-33 

Grammes. 
435 
20-34 

Grammes. 
128 
7-18 

In  one  day. 

Combustible  .  .  . 

8-551 

72-75 

47-50 

39-45 

12-8 

Proportion  .  . 

1 

8-5 

5-5 

4-6 

1-5 

Incombustible.  . 

0-747 

2-79 

3-03 

1-849 

0-^18 

Proportion  .  . 

1 

3-73 

4-06 

2-47 

0-96 

In  looking  at  these  figures  we  must  remember  that 
Ahrens  could  only  determine  what  the  overground  part 
of  the  plant  had  received  from  the  root,  not,  as  Ander- 
son in  the  case  of  the  turnip,  what  the  whole  plant  had 
derived  from  the  soil.  The  great  disparity  in  the  in- 
crease of  combustible  and  incombustible  substances 
evidently  depends  rather  upon  the  unequal  distribution 
of  the  materials  absorbed,  than  upon  any  disparity  in 
the  quantity  derived  from  the  soil.  The  whole  period 
of  developement  comprised  about  92  days,  and  we  see 
that  for  more  than  the  first  half  (49  days)  the  plant  re- 
mains stationary  at  an  apparently  low  stage  of  growth, 
the  foliage  alone  being  developed,  and  that  not  fully. 
In  the  next  12  days,  from  the  18th  to  the  30th  June, 
the  plant  gains  double  the  weight  of  incombustible  con- 
stituents, and  grows  twice  as  high  as  in  the  49  days 
preceding  ;  and  within  this  short  time,  the  overground 
parts  absorb  nearly  the  same  quantity  of  incombustible 
constituents  as  they  had  previously  taken  up.  In  fact, 
the  plant  takes  up  8J  times  the  quantity  of  combustible 
matter,  and  3f  times  more  of  ash  constituents  on  one 
day  of  shooting,  than  upon  one  of  the  49  previous  days. 

We  cannot  suppose  it  at  all  likely  that  the  external 
conditions  of  nutrition,  the  supply  of  food  by  the  atmos- 
phere and  from  the  ground,  or  the  absorptive  power  of 


GROWTH   OF   THE   OAT-PLANT. 


51 


the  plant,  should  alter  and  increase,  by  fits  and  starts, 
from  one  day  to  another.  We  are  led  rather  to  assume 
that  the  oat-plant  is  subject  in  its  developement  to  the 
same  law  which  we  have  observed  in  the  case  of  the 
turnip,  and  that  therefore,  in  the  second  half  of  the  first 
stage  of  growth,  the  activity  of  the  leaves  was  princi- 
pally directed  to  the  production  of  organisable  matter, 
to  be  stored  up  in  the  root  in  the  shooting  stage,  and 
then  supplied  to  the  overground  organs  of  the  plant. 
The  heightened  assimilative  or  working  power  of  the 
plant,  consequent  upon  the  higher  temperature  and 
brighter  sunshine  of  summer,  was  attended  by  a  pro- 
portionate increase  in  the  supply  of  food  ;  but  the  rela- 
tive proportion  of  the  soil  constituents  remained  much 
the  same  as  in  the  turnip  plant. 

If  we  compare  the  respective  quantities  of  potash, 
phosphoric  acid,  and  nitrogen,  which  the*  overground 
parts  of  the  oat-plant  have  received  from  the  root  and 
the  soil,  in  the  several  stages  of  growth,  i.  e.  to  the 
commencement  of  flowering,  thence  to  incipient  ripen- 
ing, and  finally  to  maturity,  we  find  that  1,000  plants 
have  received : — 


In  the  I.  and  II. 

stages,  61  days. 

In  the  Ii  and  IK 
stages,  21  days. 

In  the  V.  stage, 
10  days. 

Potash  

Grammes. 
34-11 

Grammes. 
18-2 

Grammes. 
O'O 

Nitrogen  

25-0 

24-9 

5-4 

Phosphoric  acid  .... 

5-99 

6'94 

1-33 

These  proportions  show  that  the  daily  increase  of 
potash  in  the  overground  parts  of  the  oat-plant  was 
pretty  nearly  the  same  in  the  21  days  of  the  3rd  and 
4th  stages,  as  in  the  61  days  of  the  1st  and  2nd.  But 
for  the  phosphoric  acid  and  the  nitrogen  a  very  differ- 
ent result  is  obtained ;  we  find  that  the  quantity  of 
these  two  ingredients  which  passed  into  the  stalk,  the 
ear,  and  the  leaves,  amounted  in  the  21  days  of  the  3rd 
and  4th  stages  to  as  much  as  in  the  61  days  of  the  1st 
and  2nd  stages  :  in  other  words,  the  overground  organs 


52  THE   PLA^T. 

of  the  plant  gained  of  these  two  ingredients,  in  the 
flowering  and  ripening  time,  three  times  as  much  each 
day  as  in  the  preceding  period. 

Of  the  turnip- plant  we  know  with  tolerable  certain- 
ty, that  from  the  time  when  it  sends  forth  a  flower- 
stalk,  the  constituents  of  the  stalk,  as  also  those  of  the 
flowers  and  the  seeds,  are  for  the  most  part  stored  up 
in  the  root,  and  are  supplied  therefrom.  It  is  highly 
probable  that  the  corn-plant  is  similarly  circumstanced, 
and  that  from  the  flowering  to  the  end  of  life  it  is  fed, 
though  not  exclusively,  by  the  root,  which  from  the 
flowering  time  gives  out  what  it  had  stored  up  in  the 
preceding  period. 

EJSTOP  observed  that  Indian  corn  plants  in  flower, 
taken  out  of  the  ground  and  placed  with  their  roots 
simply  in  water,  produced  ears  with  ripe  seeds  ;  which 
proves  that  the  materials  serving  for  the  production  of 
seed  were  already  present  in  the  plant  at  the  time  of 
flowering. 

It  is  an  established  fact  that  a  corn-plant,  if  cut  off 
before  flowering,  relapses  into  that  lower  stage  of  vege- 
tation of  a  perennial  plant,  in  which  the  root  receives 
more  organisable  matter  than  it  parts  with.* 

The  proportions  of  incombustible  constituents  and 
of  nitrogen  severally  required  by  oats  and  turnips,  are 
remarkably  different  both  in  the  aggregate  and  during 
the  various  stages  of  growth.  The  facts  established  by 
Anderson  for  the  turnip,  and  by  Ahrends  for  the  oat, 
are  indeed  not  sufficiently  numerous  to  warrant  us  in 
deducing  any  positive  law  of  growth  for  those  two 
plants  :  "still  a  few  inferences  may  easily  be  drawn  from 
them.  The  quantities  of  phosphoric  acid  and  nitrogen 
in  the  turnip  are,  at  the  end  of  the  first  year  of  vegeta- 
tion, nearly  in  the  proportion  of  1 : 1 ;  in  oats,  on  the 
contrary,  of  1 :  4,  The  oat-plant  requires  to  the  same 
quantity  of  phosphoric  acid  four  times  as  much  nitrogen 

*  Buckmann  ('  Journ.  of  the  Royal  Agric.  Soc.')  sowed  wheat  on  a 
field  in  autumn  1849,  which  was  continually  cut  down  in  1850,  so  that  the 
plants  were  never  allowed  to  come  to  flower :  they  were  left  in  during  the 
winter  1850-51,  and  yielded  an  excellent  crop  in  the  year  1851. 


GROWTH  OF  TUKNIPS  AND  OATS  COMPARED.     53 

as  the  turnip ;  and  the  latter  to  the  same  quantity  of 
nitrogen  four  times  as  much  phosphoric  acid. 

If  the  developement  of  the  oat-plant  takes  a  similar 
course  to  that  of  the  turnip,  the  former  must  have  ac- 
cumulated in  its  underground  organs  before  the  time  of 
shooting  a  store  of  organisable  matter,  similar  to  that 
laid  up  by  the  turnip  at  the  close  of  the  first  year  of 
vegetation.  The  mass  of  organic  substances  accumu- 
lating in  these  plants  before  the  developement  of  the 
flower-stalk  is  manifestly  much  larger  in  the  turnip 
than  in  the  oat-plant.  The  former  receives  from  the 
soil  much  more  phosphoric  acid  and  nitrogen  ;  but  the 
turnip  had  122  days,  the  oat-plant  only  50  days,  up  to 
the  period  of  shooting  for  extracting  these  nutritive 
substances  from  the  ground.  Now  if  the  turnips  and 
oats  growing  on  a  hectare  (2-J-  acres)  of  land  had  daily 
received  an  equal  amount  of  them,  then,  all  other  cir- 
cumstances being  the  same,  the  quantity  of  nutritive 
substances  absorbed  would  be  proportionate  to  the  time 
of  absorption.  In  this  respect  the  nature  of  the  root- 
makes  a  great  difference,  according  to  the  extent  of  ab- 
sorbent root-surface.  The  larger  root-surface  is  in  con- 
tact with  more  earthy  particles,  and  can  during  the 
same  time  extract  more  nutritive  substances  than  the 
smaller.  The  mass  of  vegetable  substance  produced, 
and  especially  the  quantity  of  non-nitrogenous  and  azo- 
tised  materials,  depend  upon  the  nature  of  the  plants. 
If  the  absorbent  root-surface  of  the  oat-plant  were  2*45 
times  greater  than  that  of  the  turnip,  the  former  would, 
under  like  circumstances,  take  up  daily  2*45  times  as 
much  food  as  the  latter,  i.  e.  the  oat-plant  would  absorb 
in  50  days  as  much  as  the  turnip  in  122  days.  Thus 
in  equal  times  the  power  of  two  plants  to  absorb  food  is 
in  proportion  to  their  absorbent  root-surface. 

The  time  of  vegetation  occupied  by  the  turnip-plant 
comprises,  in  the  first  year,  120  to  122  days,  and  termi- 
nates at  the  end  of  July  in  the  next  year  with  the  pro- 
duction of  seed.  If  we  take  the  whole  time  of  vegeta- 
tion of  the  turnip-plant  at  244  days,  and  suppose  the 
time  of  vegetation  of  the  oat-plant  extended  from  93  or 


54  THE   PLANT. 

95  to  244  days,  we  find  that  this  would  give  sufficient 
time  for  growing  two  oat  crops,  and  advancing  a  third 
half  way  to  maturity  ;  and  a  careful  investigation  might 
perhaps  reveal  that  the  quantity  of  sulphureous  and 
nitrogenous  constituents  produced  in  the  oat-plant  is 
not  less  than  that  obtained  in  turnip-plants  from  an 
equal  area  of  ground. 

In  the  grains  of  the  cereals  the  quantity  of  the  sul- 
phureous and  nitrogenous  constituents  is  to  that  of  the 
non-nitrogenous  (the  quantity  of  the  blood-making  sub- 
stances to  the  amylum),  as  1:4  or  5  ;  in  the  roots  of 
turnips,  or  in  the  tubers  of  potatoes,  as  1 :  8  or  10.  In 
the  latter,  therefore,  the  quantity  of  the  non-nitrogenous 
constituents  is  in  proportion  to  the  other  constituents 
much  greater. 

"When  at  a  certain  temperature  the  organic  process 
of  germination  begins  in-  a  grain  of  wheat,  the  embryo 
first  sends  down  a  number  of  rootlets,  while  the  plumule 
rises  upward  in  the  form  of  a  short  stem,  with  two 
or  three  complete  leaves.  Simultaneously  with  the 
changes  taking  place  in  the  embryo,  the  constituents 
of  the  farinaceous  body  (albumen)  become  fluid ;  the 
amylum  is  converted  first  into  a  substance  resembling 
gum,  then  into  sugar,  while  the  gluten  changes  into 
albumen,  and  both  together  form  protoplastem  (Naege- 
li's  organic  food  elements),  or  the  food  of  the  cell.  The 
fluidity  of  the  new  body  enables  it  to  find  its  way  to 
the  places  where  the  formation  of  cells  is  going  on. 
The  amylum  supplies  the  elements  required  to  form  the 
outer  wall  of  the  cell ;  the  nitrogenous  matter  consti- 
tutes a  principal  ingredient  of  the  cell  contents.  Simul- 
taneously with  the  roots  and  leaves,  small  leaf-buds  arise 
upwards  on  the  stem-joint,  and  small  root-buds  appear 
at  the  basis  of  the  roots. 

In  the  protoplastem  of  the  wheat-plant  the  non- 
nitrogenous  matter  exceeds  the  azotised  matter  as  five 
to  one. 

Except  water  and  oxygen,  no  substance  from  with- 
out takes  any  part  in  these  processes.  What  the  seed 
loses  in  carbon  by  the  formation  of  carbonic  acid  in 


FIRST   GROWTH   OF   A   GRAIN   OF   WHEAT.  55 

germination  is  afterwards  recovered  almost  entirely  by 
the  young  plant. 

The  plant  developed  under  these  circumstances 
barely  increases  in  substance  to  any  appreciable  degree, 
even  though  it  may  continue  vegetating  for  weeks. 
The  organs  developed  from  a  grain  of  wheat  weigh  all 
together,  when  dried,  no  more  than  the  grain  did  before 
germination.  The  relative  proportion  of  the  non-nitro- 
genous and  azotised  substances  in  them  is  almost  the 
same  as  in  the  farinaceous  body,  the  constituents  of 
which  have  in  reality  merely  assumed  other  forms. 
The  leaves,  roots,  stem,  leaf-buds  and  root-buds  collect- 
ively represent  the  constituent"  parts  of  the  seed,  trans- 
formed into  organs  and  apparatus  now  endued  with  the 
power  of  performing  certain  operations  which  serve  to 
carry  on  a  chemical  process,  whereby  external  inorganic 
substances,  with  the  cooperation  of  sunlight,  are  con- 
verted into  products  analogous  in  all  their  properties  to 
the  materials  from  which  these  organs  themselves  arose. 

The  organic  process  of  cell-formation  presupposes 
the  presence  of  the  protoplasm,  and  is  independent  of 
the  chemical  process  by  which  the  latter  is  generated ; 
but  this  chemical  process  is  indispensable  to  the  con- 
tinuance of  the  cell-formation. 

In  a  young  plant  which  has  been  developed  in  pure 
water  alone,  the  chemical  process  must  soon  come  to  an 
end  for  want  of  the  necessary  external  conditions.  The 
leaves  and  roots  in  this  case  can  do  no  work  as  formative 
organs.  In  the  absence  of  food  they  generate  no  products 
upon  which  the  continued  existence  of  the  plant  de- 
pends. When  they  have  arrived  at  a  certain  state  of 
developement,  the  cell-formation  ceases  in  themselves, 
although  it  is  still  continued  in  the  new  root-buds  and 
leaf-buds.  The  latter  stand  to  the  movable  contents  of 
the  previously  existing  leaves  and  roots  in  the  same  re- 
lation as  the  embryo  of  the  w^eat-seed  to  the  farina- 
ceous body.  The  non-nitrogenous  and  azotised  constit- 
uents which  represent  the  working  capital  of  the  exist- 
ing roots  and  leaves  are  transformed  as  these  die  into 
new  organs,  and  new  leaves  are  developed  at  the  ex- 


56  THE    PLANT. 

pense  of  the  constituents  of  the  old  ones.  But  these 
processes  are  of  short  duration  ;  after  a  certain  number 
of  days  the  young  plant  dies.  The  more  immediate  ex- 
ternal cause  of  its  short  duration  is  the  want  of  food ; 
but  another  internal  cause  is  the  conversion  of  the  non- 
nitrogenous  soluble  substances  into  cellulose  or  woody 
tissue,  whereby  it  loses  mobility.  With  the  diminution 
of  this  soluble  substance  the  most  essential  condition  of 
cell-formation  is  impaired :  when  the  whole  has  been 
consumed,  the  process  comes  to  an  end.  The  withered 
leaves,  when  burnt,  leave  behind  a  certain  quantity  of 
ash,  showing  that  they  retain  some  mineral  matter ; 
there  remains  in  them  also  a  small  portion  of  nitroge- 
nous substance. 

The  most  remarkable  thing  in  this  developement  is 
the  part  performed  by  the  nitrogenous  matter  of  the 
seed,  which  becomes  a  constituent  element  of  the  root- 
fibres,  stems,  and  leaves,  where  its  agency  serves  to 
bring  about  the  formation  of  cells.  After  the  death  of 
the  first  leaves,  it  becomes  a  constituent  of  the  new 
ones,  performing  in  them  the  same  part  over  again,  so 
long  as  there  remains  materials  for  cell-formation.  But 
the  nitrogenous  matter  itself  is  not  in  reality  worked  up 
in  the  plant,  and  forms  no  actual  tissue  or  component 
part  of  the  cell. 

The  experiments  of  BOUSSINGAULT  on  the  growth  of 
plants,  in  the  absence  of  all  nitrogenous  food  ('  Annal. 
de  Chim.  et  de  Phys.,'  ser.  iii.,  xliii.,  p.  149),  though 
undertaken  for  a  different  purpose,  are  well  adapted  to 
remove  all  doubt  about  the  very  important  power  pos- 
sessed by  the  nitrogenous  matter  just  now  alluded  to, 
viz.  of  mg|intaining  the  vital  process  in  the  plant,  even 
where  the  mass  of  the  plant  itself  receives  no  increase. 

In  these  experiments  lupines,  beans,  oats,  wheat, 
and  cresses  were  sown  in  pure  pumice-stone  dust,  washed 
and  burnt,  with  which  was  mixed  a  certain  quantity  of 
ash  from  stable-manure  and  from  seeds  similar  to  those 
sown.  The  plants  were  grown  partly  under  glass  bells, 
with  a  constantly-renewed  supply  of  air  containing  car- 
bonic acid.  The  air  supplied  and  the  water  used  for 


FUNCTION   OF   THE    NITROGENOUS   MATTER   OF    SEEDS.      57 

the  plants,  were  most  carefully  freed  from  ammonia. 
The  results  of  these  experiments  were  as  follows  : — In 
an  experiment  where  the  plants  were  grown  under  a 
glass  bell,  4'780  grammes  of  seeds  (lupines,  beans,  and 
cresses),  containing  0'227  gramme  of  nitrogen,  gave 
16*6  grammes  of  dried  plants ;  adding  the  amount  of 
nitrogen  in  the  soil,  0*224  gramme  ot  that  element  was 
recovered.  In  another  experiment,  where  the  plants 
were  grown  in  free  atmospheric  air,  with  the  exclusion, 
however,  of  dew  and  rain,  4*995  grammes  of  seeds  (lu- 
pines, beans,  oats,  wheat,  and  cresses)  gave  18*73 
grammes  of  dried  plants.  The  seeds  contained  0*2307 
gramme  of  nitrogen ;  the  plants  and  soil,  0*2499 
gramme.  In  the  first  series  of  experiments  all  ele- 
ments of  food  were  supplied  to  the  plants,  except  nitro- 
gen ;  the  chief  conditions  required  to  form  unazotised 
matter  were  given,  but  those  required  to  form  azotised 
matter  were  altogether  excluded. 

The  growth  of  a  wheat  plant  in  pure  water  and  at- 
mospheric air  is  unattended  with  any  increase  of 
weight.  The  normal  seed-corn  contains  a  certain  quan- 
tity of  potash,  magnesia,  and  lime,  which  are  required 
internally  for  the  organic  formative  process  ;  but  it  has 
no  excess  of  those  mineral  substances  that  could  serve 
to  effect  the  chemical  process  of  a  new  production  of 
protoplasm.  Where  the  mineral  substances  are  ex- 
cluded, the  organs  will  absorb  water,  but  neither  car- 
bonic acid  nor  ammonia  ;  at  all  events,  these  two  latter 
substances,  even  though  they  be  introduced  into  the 
plant  by  means  of  the  water,  exert  no  influence  upon 
the  internal  process  ;  they  suffer  no  decomposition,  and 
no  vegetable  matter  is  formed  from  their  elements. 

In  Boussingault's  experiments,  the  action  of  the 
mineral  substances  supplied  is  unmistakable.  The 
weight  of  the  plants  produced  was  nearly  3^  times 
greater  than  that  of  the  seeds  sown  :  but  the  quantity 
of  nitrogenous  matter  was  the  same  as  in  the  seeds. 
Hence  we  have  a  clear  production  of  non-nitrogenous 
substance  2-J-  times  more  than  the  original  weight  of 
the  seeds.  A  simple  calculation" shows  that  the  nitro- 

8* 


58  THE   PLANT. 

gen  in  the  seed  has,  under  these  circumstances,  caused 
the  generation  of  56  times  its  own  weight  of  unazotised 
matter ;  or,  what  comes  to  the  same  thing  (taking  the 
amount  of  carbon  in  the  latter  at  44  per  cent,  only),  the 
decomposition  of  90  times  its  own  weight  of  carbonic 
acid. 

The  course  of  vegetation  in  these  plants  throws 
sufficient  light  upon  the  processes  going  on  in  their  or- 
ganism ;  in  the  first  days  their  developement  was  vig- 
ourous,"  afterwards  languid.  The  first-formed  leaves 
withered  after  a  time,  and  partly  dropped  off,  fresh 
leaves  being  developed  in  their  stead,  which  went  on  in 
the  same  way ;  and  the  vegetation  seemed  to  reach  a 
point  where  the  newly  developed  parts  existed  at  the 
expense  of  the  decaying  portions.  A  French  bean, 
weighing  0*755  gramme,  planted  on  the  10th  May,  had 
by  the  30th  July  developed  17  leaves,  of  which  the  first 
11  were  then  dead  and  gone.  The  plant  flowered,  and 
on  the  22nd  August,  when  nearly  all  the  leaves  had 
dropped  off,  produced  a  single  small  bean,  which 
weighed  4  centigrammes,  the  T^th  part  of  the  weight 
of  the  seed-bean.  The  entire  crop  weighed  2*24 
grammes,  very  nearly  three  times  as  much  as  the  seed- 
bean.  In  the  case  of  a  rye-plant  it  was  very  clearly 
observed  how  the  unfolding  of  every  fresh  leaf  was  at- 
tended with  the  death  of  one  of  the  old  leaves. 

In  the  second  series  of  experiments,  the  plants  had 
absorbed  (from  the  air)  1*92  milligramme  of  nitrogen, 
and  produced  0.830  gramme  more  vegetable  substance, 
giving  43  milligrammes  of  unazotised- matter  for  every 
milligramme  01  nitrogen. 

The  difference  in  the  developement  of  a  plant  in 
pure  water  from  that  of  one  grown,  as  in  Boussingault's 
experiments,  in  a  soil  supplying  the  incombustible  con- 
stituents of  food,  is  clear  and  unequivocal.  The  organs 
first  formed  received  in  both  cases  their  elements  from 
the  seed ;  in  both,  a  certain  quantity  of  mineral  sub- 
stances and  also  of  soluble  unazotised  matter  was  con- 
sumed to  form  cellulose  in  the  leaves,  roots,  and  stems  ; 
and  the  proportion  of  the  unazotised  to  the  nitrogenous 


DIFFERENCE   IN   DEVELOPEMENT.  59 

matter  was  altered.  In  the  plant  growing  in  water, 
there  was  a  constant  decrease  of  uriazotised  matter ; 
while  in  the  other  a  certain  quantity  of  that  substance 
was  generated  anew.  Nothing  can  be  more  certain 
than  that  in  Boussingault's  experiments,  the  first-formed 
leaves  acquired  by  the  supply  of  mineral  substances  the 
faculty  of  absorbing  and  decomposing  carbonic  acid,  a 
power  not  possessed  by  the  plant  developed  in  pure 
water  ;  and  that  as  much  soluble  unazotised  substance 
was  reproduced  as  had  been  consumed  in  the  formation 
of  the  leaves  and  roots  by  the  conversion  into  cellulose 
of  the  store  originally  present. 

In  the  movable  constituents  of  the  plant,  the  rela- 
tive proportion  between  the  unazotised  and  the  azotised 
seed  constituents  was  manifestly  restored  pretty  nearly 
as  it  existed  in  the  seed ;  both  matters  passed  through 
the  stem  into  every  new-formed  leaf-bud,  and  took  part 
in  the  developement  of  new  leaves,  by  whose  operation 
the  consumption  of  unazotised  matter  was  always  made 
good  again  within  a  certain  limit,  so  that  the  same  pro- 
cess could  be  repeated  again  and  again  for  months.  In 
every  one  of  the  dead  leaves  (and  root  fibres)  a  certain 
quantity  of  the  azotised  substance  remained  behind,  and 
in  the  last  period  of  vegetation  the  floating  remainder 
of  this  substance  was  collected  in  the  pod  and  in  the 
seeds. 

The  supply  of  mineral  substances  had  served  to 
effect  the  continuance  of  the  chemical  process,  and 
caused  the  production  of  unazotised  substances.  By 
the  presence  of  these  mineral  bodies,  and  by  the  coop- 
eration of  the  azotised  matters,  new  material  was  en- 
gendered from  carbonic  acid  to  form  the  cell-walls,  and 
the  term  of  life  was  prolonged  to  its  proper  limit.  The 
most  remarkable  point  is,  that  a  quantity  comparatively 
so  small,  of  azotised  substance  derived  from  the  seed, 
should  so  long  be  able  to  perform  its  assigned  functions, 
apparently  without  suffering  any  alteration  ;  so  that  in 
the  body  of  the  living  plant,  made  to  produce  and  col- 
lect it,  it  would  seem  to  possess  a  kind  of  indestructi- 
bilitv. 


60  THE   PLANT. 

If  we  consider,  that,  in  the  cited  experiment  with 
the  French  bean,  a  great  part  of  the  additional  unazo- 
tised  substances  which  were  produced  fell  away  in  the 
dying  leaves  from  the  body  of  the  plant,  it  will  be  seen 
that  the  supply  of  mineral  substances  was  of  110  use  to 
the  bean-plant  in  the  absence  of  nitrogenous  food. 

Lastly,  it  is  quite  intelligible  that  the  amount  of 
azotised  matter  contained  in  a  bean  might  perhaps  suf- 
fice to  sustain  for  years  the  vegetation  of  one  of  the 
conifers  with  persistent  leaves,  and  to  produce  many 
hundred  —  perhaps  many  thousand  —  times  its  own 
weight  of  woody  substance  ;  and  that  such  a  plant 
upon  a  barren  soil  altogether  unsuited  for  other  plants, 
might  thrive  with  a  very  sparing  supply  of  nitrogenous 
food,  if  the  soil  contained  a  proper  store  of  those  min- 
eral substances  which  are  indispensable  for  the  genera- 
tion of  unazotised  matter. 

The  growth  of  a  plant  essentially  consists  in  the  en- 
largement and  multiplication  of  the  organs  of  nutrition, 
i.  e.  the  leaves  and  roots.  The  enlargement  of  the  first, 
or  the  production  of  a  second  leaf  or  root  fibre,  requires 
the  same  conditions  as  the  production  of  the  first.  The 
analysis  of  the  seeds  teaches  us  with  tolerable  certainty 
what  these  conditions  are.  In  the  normal  conditions  of 
nutrition,  the  first  roots  and  leaves,  whose  elements  were 
supplied  by  the  seed,  produce  from  certain  mineral  sub- 
stances organic  compounds,  which  become  parts  and 
constituents  of  themselves,  or  constituents  of  fresh  leaves 
and  roots,  consisting  of  the  same  elements  and  having 
the  identical  properties  of  the  first,  i.  e.  they  possess  the 
same  power  to  transform  inorganic  nutritive  substances 
into  organic  formative  materials. 

It  is  quite  clear  that  the  enlargement  of  the  first 
leaves  and  roots  and  the  production  of  new  ones,  must 
have  required  azotised  and  unazotised  substances  in  the 
same  proportion  as  in  the  seed,  which  makes  it  probable 
that  the  organic  operations  of  the  plant  under  the  do- 
minion of  sunlight  uniformly  produce  in  all  periods  of 
growth  the  same  materials,  i.  e.  the  constituent  ele- 
ments of  the  seed,  which  serve  to  build  up  the  plant, 


FUNCTION   OF   AZOTISED   MATTER   IN   PERENNIALS.       61 

being  formed  into  leaves,  stems,  and  root-fibres,  or 
finally  into  seed.  The  soluble  constituents  of  a  bud,  a 
tuber,  or  the  root  of  a  perennial  plant,  are  identical 
with  the  seed  constituents.  The  cereal  plant  produces 
azotised  and  unazotised  substances  in  the  same  propor- 
tion as  in  the  albumen  (farinaceous  body).  The  potato 
plant  produces  the  constituents  of  the  tuber,  which  are 
formed  into  leaves  and  branches  or  roots  ;  or,  if  the  ex- 
ternal conditions  are  no  longer  favourable  to  the  forma- 
tion of  leaves  and  roots,  accumulate  again  in  the  under- 
ground stem,  to  form  new  tubers.* 

While  the  growth  of  the  plant  continues,  the  first  as 
well  as  the  last  leaves  and  roots  will,  with  a  proper 
supply  of  food,  maintain  their  existence,  since  they  re- 
produce out  of  the  nutriment  supplied  to  them  the 
identical  constituents  from  which  they  themselves  arose. 
The  excess  of  these,  which  they  do  not  require  for  their 
own  enlargement,  goes  to  those  parts  of  the  plant  where 
the  motion  of  the  fluids  or  the  cell-formation  is  most 
active, — viz.,  to  the  roots,  the  leaf-buds,  or  the  extreme 
points  of  the  roots  and  shoots ;  and,  finally,  as  in  the 
case  of  summer  plants,  to  the  organs  of  seed-formation 
which  at  the  ripening  of  the  seed  absorb  most  of  the 
movable  seed-constituents  existing  in  the  plant. 

The  supply  of  the  incombustible  elements  of  food 
led  to  the  formation  of  unazotised  matter,  a  portion  of 
which  was  used  to  form  woody  tissue,  whilst  another  por- 
tion remained  available  for  the  same  purpose.  The  supply 
of  nitrogenous  food  caused  a  corresponding  production 
of  nitrogenous  matter,  so  that  the  protoplasm  was  con- 
stantly renewed,  and,  so  long  as  the  chemical  process 
lasted,  was  increased. 

*  Boussingault  has  observed  that  even  seeds  weighing  two  or  three 
milligrammes,  sown  in  an  absolutely  sterile  soil,  will  produce  plants  in 
which  all  the  organs  are  developed,  but  their  weight,  after  months,  does 
not  amount  to  much  more  than  that  of  the  original  seed,  even  if  they 
vegetate  in  the  open  air  ;  and  the  result  is  more  marked  if  they  grow  in  a 
confined  atmosphere.  The  plants  remain  delicate,  and  appear  reduced  in 
all  dimensions;  they  may,  however,  grow,  flower,  and  even  bear  seed 
which  only  requires  a  fertile  soil  to  produce  again  a  plant  of  the  natural 
size.  (*  Compt.  rend.'  t.  xliv.  p.  940.) 


THE   PLANT. 


To  enable  a  plant  to  flower  and  bear  seed,  it  would 
appear  necessary  in  the  case  of  many  plants  that  the 
activity  of  the  leaves  and  roots  should  reach  a  period  of 
rest.  It  is  only  after  this  that  the  process  of  cell-forma- 
tion seems  to  gain  the  ascendancy  in  a  new  direction  ; 
and  the  constructive  materials  being  no  longer  required 
for  the  formation  of  new  leaves  and  roots,  are  used  to 
form  the  flower  and  the  seed.  In  many  plants  the 
want  of  rain,  and  the  consequent  deficiency  of  incombus- 
tible nutritive  substances,  will  restrain  the  formation  of 
leaves  and  hasten  the  flowering.  Dry,  cool  weather 
favours  the  production  of  seed.  In  warm  arid  moist 
climates  the  cereals  sown  in  summer  bear  little  or  no 
seed ;  and  on  a  soil  poor  in  ammonia  the  root-plants 
more  readily  flower  and  bear  seed  than  on  a  soil  rich  in 
that  substance. 

If  the  normal  processes  of  vegetation  require  a  defi- 
nite proportion  of  unazotised  and  azotised  materials  in 
the  protoplasm  which  is  formed  in  the  plant,  it  is  evi- 
dent that  the  want  or  excess  of  the  mineral  substances 
indispensable  for  the  production  of  those  matters  must 
exercise  a  very  decided  influence  upon  the  growth  of 
the  plant,  and  upon  the  formation  of  the  leaves,  roots, 
and  seed.  Want  of  azotised  and  excess  of  fixed  nutri- 
tive substances  would  lead  to  the  formation  of  unazo- 
tised materials  in  preponderating  quantity ;  but  when 
these  have  assumed  the  form  of  Cleaves  and  roots,  they 
retain  a  certain  amount  of  nitrogenous  matter,  thereby 
impairing  the  seed  formation,  a  principal  condition  of 
which  is  an  excess  of  protoplasm.  An  excess  of  azotised 
food,  with  a  deficiency  of  fixed  nutritive  substances,  will 
be  of  no  use  to  the  plant  itself,  because  the  latter  can 
for  its  organic  operations  make  use  of  nitrogenous  sub- 
stances only  in  proportion  as  they  exist  in  the  proto- 
plasm, and  the  contents  of  the  cell  are  of  no  value  to 
the  plant  in  the  absence  of  the  materials  required  to 
form  the  cell-walls. 

In  the  process  of  animal  life  the  organs  of  the  body 
are  constructed  from  the  elements  of  the  egg  ;  the  con- 
stituent parts  of  such  constructed  organs  are  azotised, 


ABSORPTION  BY  THE  BOOTS   OF  PLANTS   NOT  OSMOTIC.     63 

whereas  in  the  plant  they  contain  no  nitrogen.  All 
processes  of  vegetative  life  tend  simply  to  produce  the 
elements  of  the  seed.  The  plant  only  lives  in  generat- 
ing the  egg-constituents  and  the  egg  itself ;  the  animal 
only  lives  by  destroying  these  very  egg-constituents. 

On  one  and  the  same  soil  equally  suited  for  the  tur- 
nip and  the  wheat-plant,  the  former  produces  for  the 
same  amount  of  azotised  substance  twice  as  much  un- 
azotised  matter  as  the  latter.  It  is  manifest  that  if  two 
plants  produce  within  the  same  time  different  quanti- 
ties of  hydrates  of  carbon  (wood,  sugar,  and  amylum), 
the  organs  of  decomposition  must  be  arranged  in  a  man- 
ner not  only  to  afford  adequate  room  for  the  carbonic 
acid  supplying  the  carbon,  and  for  the  water  supplying 
the  hydrogen,  as  well  as  to  present  a  suitable  extent  of 
surface  to  the  action  of  the  light,  but  also  to  permit  the 
liberated  oxygen  to  escape  as  promptly  as  it  becomes 
free.  If  we  compare  in  this  respect  the  leaves  of  a 
wheat-plant  with  those  of  a  turnip-plant,  we  find  a 
striking  difference  in  their  size,  and  in  the  amount  of 
water  respectively  contained  in  them  ;  and  a  microscopic 
examination  reveals  still  greater  differences.  The  wheat- 
plant  has  erect  leaves,  which  present  to  the  light  a 
much  smaller  surface  than  the  leaves  of  the  turnip- 
plant,  which  overshadow  the  ground,  preventing  the 
drying  of  the  soil  and  the  exhalation  from  it  of  carbonic 
acid.  In  the  wheat-leaf  the  stomates  are  equally  thick 
on  both  sides ;  in  the  turnip-leaf  they  are  much  more 
numerous,  although  smaller  than  in  the  wheat-leaf,  and 
a  far  greater  number  of  them  are  found  on  the  lower 
than  on  the  upper  side. 

All  the  facts  known  respecting  the  nutrition  of 
plants  tend  to  prove  that  it  is  not  by  a  mere  osmotic 
process  that  they  absorb  their  food,  but  that  the  'roots 
perform  a  very  definite  active  part  in  selecting  from  the 
amount  of  food  presented  to  them  such  matters  and  in 
such  quantities  as  are  best  suited  to  the  plant. 

The  influence  of  the  roots  is  most  manifest  in  the 
vegetation  of  marine  and  fresh-water  plants,  whose  roots 
are  not  in  contact  with  the  soil. 


64  THE    PLANT. 

These  plants  received  their  incombustible  nutritive 
substances  from  a  solution  in  which  these  elements  are 
most  uniformly  mixed  and  diffused ;  and  yet  a  com- 
parative analysis  of  the  water  and  the  ash-constituents 
of  these  plants  shows  that  each  species  absorbs  from  the 
same  solution  different  quantities  of  potash,  lime,  silicic 
acid,  and  phosphoric  acid. 

The  ash  of  duckweed  was  found  to  contain  22  parts 
of  potash  to  10  parts  of  chloride  of  sodium,  whereas  the 
water  in  which  the  plant  had  grown  contained  only  4 
parts  of  potash  to  10  parts  of  chloride  of  sodium.  In 
the  plant  the  relative  proportion  of  the  sulphuric  acid 
to  the  phosphoric  acid  was  10  to  14 ;  in  the  water,  10 
to  3. 

It  is  quite  the  same  with  marine  plants.  Sea-water 
contains  for- 25  or  26  parts  of  chloride  of  sodium  1'21  to 
1*35  of  chloride  of  potassium ;  but  the  plants  growing 
in  it  contain  more  potash  than  soda.  The  kelp  of  the 
Orkney  Islands,  which  consists  of  the  ashes  of  many 
species  of  fucus,*  contains  for  26  per  cent,  of  chloride 
of  potassium  only  19  per  cent,  of  chloride  of  sodium. 

Sea-water  contains  manganese,  but  in  such  exceed- 
ingly small  quantity  that  it  would  certainly  have 
escaped  analysis,  were  it  not  invariably  found  among 
the  ash-constituents  of  many  marine  plants.  The  ash 
of  jPadina  pavonia  (a  species  of  tang)  is  found  to  con- 
tain of  this  mineral  even  more  than  8  per  cent,  of  the 
weight  of  the  dried  plant.f 

By  the  same  power  of  selection  the  laminaria  with- 
draw from  the  sea-water  in  which  they  grow  the  iodine 
compounds  present  in  it  in  such  exceedingly  minute 
quantities.  Chloride  of  potassium  and  chloride  of  sodi- 
um have  the  same  form  of  crystallisation,  and  so  many 

*  See  Godechen's  analysis  of  the  ash  of  different  species  of  fucus. 
(<  Annal.  d.  Chem.  und  Pharm.' liv.  351.) 

f  To  give  some  idea  of  the  extraordinary  power  which  this  plant  must 
possess  to  withdraw  the  manganese  from  sea-water,  I  need  simply  state 
that  the  quantity  of  this  metal  in  sea-water  is  so  exceedingly  small,  that  I 
could  find  distinct  traces  of  it  only  by  subjecting  the  sesquioxide  of  iron, 
obtained  from  twenty  pounds  of  sea-water,  to  a  most  searching  analysis. 
(Forchhammer  and  Poggendorff,  xcv.  p.  84.) 


OSMOSIS    AND   ABSORPTION   BY    ROOTS.  65 

other  properties  in  common,  that  without  the  aid  of 
chemical  means  we  cannot  accurately  distinguish  the  one 
from  the  other.  But  the  plant  clearly  discriminates 
between  the  two  salts,  for  it  separates  the  one  from  the 
other,  and  for  every  one  equivalent  of  potassium  which 
it  absorbs  leaves  behind  in  the  water  more  than  thirty 
equivalents  of  sodium.  Manganese  and  iron,  iodine 
and  chlorine,  are  likewise  isomorphous  bodies  ;  yet  the 
iodine  plant  separates  one  equivalent  of  iodine  in  sea- 
water  from  many  thousand  equivalents  of  chlorine. 

The  known  laws  of  osmosis,  and  of  the  diffusion  or 
interchange  of  water  and  salts  through  a  dead  mem- 
brane or  a  porous  mineral  body,  give  no  explanation 
whatever  of  the  action  exercised  by  a  living  membrane 
upon  salts  in  solution,  or  how  they  pass  through  it  into 
the  plant.  The  observations  of  Graham  ('  Phil.  Mag.' 
ser.  IV.  August  1850)  show  that  matters  capable  of 
exerting  a  chemical  action  upon  animal  membranes, 
such  as  carbonate  of  potash  and  caustic  potash,  causing 
them  to  swell  and  gradually  decomposing  them,  facili- 
tate the  passage  of  water  to  an  extraordinary  degree.* 
Graham  remarks  that  the  processes  of  alteration,  decom- 
position, and  new  formation,  which  are  incessantly 
taking  place  in  the  membranes  and  cells  in  all  parts  of 
the  plant,  and  which  we  have  no  means  of  denning  or 
measuring,  must  entirely  change  the  osmotic  process : 
the  permeation  of  mineral  substances  through  the  living 
vegetable  membrane  must,. therefore,  be  governed  by 
very  complex  laws. 

Land  plants  act  in  the  same  manner  with  respect  to 
the  soil  in  which  they  grow,  as  marine  plants  to  sea- 

*  The  water  in  the  tubes  of  his  osmometer  rose  to  167  millimeters, 
when  holding  1/1  Om.  per  cent,  of  carbonate  of  potash  in  solution;  with  1 
per  cent,  of  that  salt,  it  rose  to  863  millimeters  (38  inches,  English).  In 
another  experiment,  the  water  holding  1  per  cent,  of  sulphate  of  potash  in 
solution,  rose  to  twelve  millimeters  ;  upon  the  addition  of  1/10  percent,  of 
carbonate  of  potash  to  the  solution,  it  rose  to  254-264  millimeters ;  .the 
same  potash  solution  by  itself  rose  only  to  92  millimeters.  The  notion  of 
an  osmotic  equivalent  is  altogether  inadmissible,  if  the  membrane  is 
chemically  altered.  Graham's  latest  investigations  on  the  dialysis  of- 
crystalline  and  amorphous  bodies  are  extremely  interesting,  and  promise  to 
throw  considerable  light  upon  the  processes  in  the  animal  organism. 


66  THE   PLANT. 

water.  One  and  the  same  field  presents  to  the  plants 
growing  in  it,  the  alkalis,  alkaline  earths,  phosphoric 
acid,  and  ammonia,  in  absolutely  the  same  form  and 
conctition ;  but  the  ash  of  no  one  species  of  plant  ever 
shows  the  same  relative  proportions  of  component  ele- 
ments as  the  ash  of  another  species.  Even  the  parasit- 
ical plants,  which  draw  their  mineral  constituents  in  a 
certain  state  of  preparation,  from  other  plants  on  which 
they  live,  as  the  mistletoe  (  Viscuin  album),  do  not  com- 
port themselves  to  the  latter  as  a  graftling  to  a  tree,  but 
absorb  from  the  sap  very  different  proportions  of  min- 
eral constituents  ('  Annal  d.  Chem.  und  Pharm/  liv. 
363).  Now,  as  the  soil  is  perfectly  passive  in  respect  to 
the  supply  of  these  materials,  there  must  be  some 
agency  at  work  in  the  plant  itself,  which  regulates  the 
absorption  according  to  the  requirements  of  each  plant. 

The  observations  made  by  Hales  (see  Appendix  C.) 
show  that  the  exhalation  from  the  surface  of  the  leaves 
and  branches  exercises  a  powerful  influence  upon  the 
motion  of  the  fluids,  and  upon  the  absorption  of  water 
from  the  soil.  If  the  plant  drew  its  mineral  food  from 
a  solution  moving  about  in  the  soil  and  passing  imme- 
diately into  the  roots,  then  two  plants  of  different  spe- 
cies or  kind,  placed  in  the  same  conditions,  would  re- 
ceive the  same  mineral  substances  in  the  same  relative 
proportions  ;  but,  as  we  have  seen,  two  plants  belonging 
each  to  a  different  species  contain  these  substances  in 
the  most  dissimilar  proportions. 

That  a  selection  takes  place  in  the  absorption  of  food 
by  the  roots  is  a  fact  beyond  dispute. 

In  the  case  of  aquatic  plants,  which  grow  under 
water,  exhalation  is  altogether  excluded  as  a  possible 
operating  cause  of  the  passing  of  the  food  into  the  body 
of  the  plant.  In  these  plants  the  absorbent  surface 
must  exercise  very  unequal  powers  of  attraction  upon 
the  different  materials,  which  are  presented  by  the  solu- 
tion in  the  same  form  and  in  a  state  of  equal  mobility  ; 
or,  what  comes  to  the  same  thing,  the  resistance  offered 
to  their  passage  through  the  outermost  cellular  layers 
must  be  very  dissimilar.  The  case  cannot  be  different 


POWER   OF    SELECTION   BY   ROOTS   NOT   ABSOLUTE.        67 

with  the  roots  of  land-plants,  to  judge  from  the  unequal 
proportions  of  the  substances  severally  absorbed  by 
them. 

The  power  of  the  roots  to  preclude  the  passing  of 
certain  substances  from  the  soil  into  the  plant  is  not 
absolute.  Forchhammer  (Poggend.  '  Annal.'  xcv.  90) 
detected  exceedingly  minute  traces  of  lead,  zinc  and 
copper  in  the  wood  of  the  beech,  birch,  and  fir ;  and 
tin,  lead,  zinc,  and  cobalt  in  that  of  the  oak ;  but  the 
fact  that  the  outer  rind  or  bark,  in  particular,  is  found 
to  contain  metals  of  this  kind  in  perceptibly  larger 
quantities  than  the  wood,  clearly  points  to  the  acci- 
dental nature  of  their  presence,  and  to  their  taking  no 
essential  part  in  the  vital  processes  of  the  plant. 

How. small  the  quantities  of  these  metals  must  be 
which  the  roots  of  these  trees  absorb  may  be  judged 
from  the  fact  that  hitherto  chemical  analysis  has  not 
been  able  to  detect  traces  of  any  other  metal  than  man- 
ganese and  iron,  in  the  water  of  wells,  brooks,  or 
springs ;  and  their  appearance  in  these  wood-plants, 
which  during  the  growth  of  half  a  century  or  more  have 
absorbed  and  evaporated  an  immense  quantity  of  water, 
is  the  only  proof  we  possess,  that  this  water  must  actu- 
ally have  contained  these  metals  in  some  form  or  other. 

The  observations  of  DE  SAUSSTJKE,  SCHLOSSBERGER, 
and  HERTH,  show  that  the  roots  of  land  and  water 
plants  absorb  from  very  dilute  saline  solutions  water 
and  salt  in  proportions  entirely  different  from  those  in 
the  fluid ;  in  all  cases  a  greater  proportion  of  water,  and 
a  less  quantity  of  salt.  In  plants  watered  with  very 
dilute  solutions  of  salts  of  baryta,  Daubeny  found  no 
baryta,  whereas  Knop  in  similar  experiments  detected 
this  substance.  The  general  result  of  all  these  experi- 
ments is  that,  of  themselves,  the  plants  have  not  the 
power  of  offering  a  permanent  resistance  to  the  chem- 
ical action  of  salts  and  other  inorganic  compounds  upon 
the  exceedingly  fine  membrane  of  the  root. 

Most  land-plants  in  their  natural  state  in  the  soil 
can  bear  no  salt  solutions,  as  concentrated  as  in  these 
experiments,  without  sickening  and  dying ;  and  even 


THE   PLANT. 

carbonate  of  potash  and  ammonia,  which  we  certainly 
know  to  be  nutritive  substances,  act  upon  many  plants 
as  poison,  even  when  present  in  th'e  water  which  circu- 
lates in  the  ground  only  in  sufficient  quantity  to  impart 
a  blue  tint  to  red  litmus  paper.  On  the  other  hand,  it 
would  be  very  wonderful  if  the  roots  of  a  plant  outside 
the  soil,  and  in  conditions  not  suitable  to  their  nature 
should,  under  the  influence  of  evaporation,  be  impene- 
trable for  salt  solutions.* 

Those  mineral  substances  which,  like  iron,  are  con- 
stant constituents  of  all  plants,  though  present  only  in 
very  small  proportions,  must  be  regarded  very  different- 
ly from  those  metals  which  Forchhammer  found  in 
woody  plants. 

We  know  the  part  which  iron  performs  in  the  ani- 
mal organism,  in  which  it  is  present  in  comparatively 
no  larger  quantities  than  in  the  seeds  of  cereals ;  and 
we  are  fully  convinced  that,  without  a  certain  amount 
of  iron  in  the  food  of  animals,  the  formation  of  the 
blood  corpuscles,  the  agents  of  one  of  the  chief  func- 
tions of  the  blood,  is  impossible.  Hence,  by  the  law 
of  dependence,  which  links  together  the  life  of  animals 
and  plants,  we  are  compelled  to  ascribe  to  the  iron  in 
the  plant  also  an  active  part  in  its  vital  functions  so 
material  that  the  absence  of  that  metal  would  endanger 
the  very  existence  of  the  plant. 

Hitherto  chemistry  has  attributed  a  positive  part  in 
the  vital  process  of  plants  to  those  incombustible  sub- 
stances only  which  are  common  to  all,  and  which  differ 
only  in  the  relative  proportions  in  the  plants.  But 

*  If  the  long  limb  of  a  syphon-shaped  tube,  filled  with  water  and  closed 
with  thick  pieces  of  pig  or  ox  bladder  tied  over  both  openings,  is  placed  in 
salt-water  or  oil,  and  the  other  limb  is  exposed  to  the  air,  the  water 
evaporates  in  the  pores  of  the  bladder  with  which  the  short  limb  is  closed. 
By  the  capillary  action  of  the  bladder,  the  water  exuding  in  gaseous  form 
is  taken  up  again  on  the  other  side  of  the  bladder,  and  a  vacuum  is  thus 
created  in  the  interior  of  the  tube,  whence  there  is  an  increased  pressure 
upon  the  surfaces  of  both  bladders,  which  forces  the  salt-water  or  the  oil 
through  the  bladder  into  the  tube.  ('  Researches  into  some  of  the  Causes 
of  the  Motion  of  Fluids,  by  J.  v.  Liebig.  Brunswick  :  Fr.  Vie  wig  &  Son. 
1848.' — p.  67.)  A  plant  in  similar  conditions  is  just  like  a  tube  closed 
with  penetrable  porous  membranes. 


IRON   AND   ZINC   NECESSARY   FOR    PLANTS.  69 

should  the  conjecture  prove  true  that  iron  is  a  constant 
constituent  of  chlorophyll  and  of  the  leaves  of  many 
flowers,  it  may  be  assumed  that  other  metals,  found  in- 
variably present  in  certain  varieties  of  plants  (as  man- 
ganese in  Pavonia,  Zostera,  Trapa  natans,  in  many 
ligneous  plants,  several  cereals,  and  in  the  tea  shrub), 
take  part  in  the  vital  functions,  and  that  certain  pecu- 
liarities depend  upon  the  presence  of  those  metals.  The 
ash  of  Viola  calaminarw,  a  plant  which,  in  the  parts 
about  Aix-la-Chapelle,  is  held  so  strongly  indicative  of 
the  presence  of  zinc,  that  the  places  where  it  grows  are 
selected  for  opening  new  mines  in  search  of  zinc  ore,  is 
found  to  contain  oxide  of  zinc.  (Alex.  Braun.) 

As  chloride  of  sodium  and  chloride  of  potassium 
cause  some  plants  to  thrive,  so  iodide  of  potassium 
manifestly  performs  a  similar  part  in  others ;  and  if 
one  plant  may  properly  be  called  a  chlorine  plant, 
others  may  with  equal  propriety  be  termed  iodine 
plants,  or  manganese  plants.*  (Prince  Salm-Horst- 
mar.) 

The  diversity  in  the  amount  of  iodine  in  different 
varieties  of  fucus  (Gocdechens),  or  of  alumina  in  various 
kinds  of  Lycopodium  (Count  Laubach),  remains,  indeed, 
unexplained  ;  but  the  power  of  plants  to  withdraw  sub- 
stances like  iodine,  even  in  the  smallest  quantities,  from 
the  sea  water  in  which  they  grow,  and  to  accumulate 
and  retain  them  in  their  organism,  can  only  be  ex- 
plained upon  the  assumption  that  these  substances  have 
entered  into  combination  with  certain  constituent  parts 
of  the  plants,  whereby  as  long  as  the  plant  lives  they 
are  prevented  from  returning  to  the  medium  from 
which  they  were  taken.f 

*  The  examination  of  the  following  water-plants  revealed  the  presence 
of  considerable  quantities  of  manganese  and  iron  in  their  ash,  though  the 
water  in  which  they  grew  apparently  contained  no  trace  of  manganese  : — 
Victoria  regia  (in  the  leaf-stalk  principally  manganese,  in  the  leaf  iron) ; 
Nympkcea  ccerulea,  dentata,  lutea  ;  Hydrocharis  Humboldti ;  Nelumbiwn 
asperifolium.  (Dr.  Zoller.) 

f  With  respect  to  the  copper  in  the  grains  of  wheat  and  rye,  which 
Meier  of  Copenhagen  has  shown  to  be  a  constant  constituent  of  both  seeds, 
Forchhammer  (PoggendorfTs  '  Annal.'  xc.  92)  remarks : — '  It  is  an  old  and 


TO 


THE   PLANT. 


It  might  be  supposed  that  plants  become  saturated 
with  the  substances  absorbed  from  the  air  and  from  the 
soil ;  and  that  all  materials  offered  by  the  soil  in  solu- 
tion, or  made  soluble  by  the  cooperation  of  the  roots, 
are  absorbed  without  distinction.  Upon  this  assump- 
tion, only  that  substance  in  the  plant  could  of  course 
pass  into  it  from  without,  which  is  withdrawn  from  the 
solution  within  for  a  formative  purpose. 

The  investigations  made  by  Schultz-Fleeth  show 
that  Nymphcea  alba  and  Arundo  phragmites  absorb 
from  the  same  soil  and  water,  the  former  nearly  13  per 
cent.,  the  latter  4*7  per  cent.,  of  ash  constituents  ;  and 
of  these  silicic  acid  in  the  most  unequal  proportion ; 
the  ash  of  Nymphcea  alba  containing  less  than  \  per 
cent,  of  that  substance,  while  in  the  ash  of  'Arundo 
phragmites  there  are  above  71  per  cent.  Upon  the 
supposition  just  made,  an  equal  amount  of  silicic  acid  is 
offered  to  the  roots  of  both  plants,  and  they  both  take 
up  an  equal  quantity  of  it  in  proportion  to  the  volume 
of  the  sap  respectively.  In  the  reed  plant  the  silicic 
acid  is  incessantly  withdrawn  from  the  sap,  and  depos- 
ited in  a  solid  state  in  the  leaves,  the  margins  of  the 
leaves,  the  sheaths,  &c.  As  the  sap  within  contains 
less  silicic  acid  than  the  solution  without,  fresh  quanti- 
ties of  it  are  absorbed  from  the  latter  ;  but  not  so  with 
the  Nymphcea)  because  the  silicic  acid  taken  up  by  that 
plant  is  not  consumed  in  it. 

If  we  accept  the  same  reasons  for  the  passage  into 
the  plant  of  carbonic  acid  and  phosphoric  acid,  then  it 
can  possess  no  actual  power  of  selection,  but  the  per- 
meation of  the  nutritive  substances  will  depend  upon 
osmotic  conditions. 

It  certainly  cannot  be  denied  that  the  absorption  of 
nutritive  substances  depends  upon  growth  or  increase 

approved  practice  to  steep  grains  of  wheat,  intended  for  sowing,  in  a  solu- 
tion of  sulphate  of  copper.  The  usual  explanation  of  this  practice  is,  that 
sulphate  of  copper  destroys  the  sporules  of  blight  to  which  the  wheat  plant 
is  liable,  an  explanation  which  it  is  not  my  intention  to  dispute.  Still  it 
might  also  be  held,  supposing  copper  to  be  an  essential  constituent  of 
wheat,  that  the  practice  in  question  serves  to  supply  the  copper  necessary 
for  the  vigorous  growth  of  the  plant.' 


PASSAGE   OF   MATTERS   INTO   THE   ROOTS.  71 

in  mass  ;  for  as  it  is  certain  that  a  plant  will  not  grow 
if  no  food  is  offered  to  it,  so  it  is  equally  certain  that  it 
will  absorb  no  nutriment  if  the  external  conditions  are 
not  favourable  to  growth.  Yet  the  view  given  above 
would  force  us  to  conclusions  which  are  not  founded  in 
nature ;  such  as,  for  instance,  (1)  that  there  is  actually 
around  the  roots  a  solution  containing  all  the  ash  con- 
stituents of  the  plants ;  and  (2)  that  the  roots  of  all 
plants  have  a  similar  structure,  and  their  sap  is  of  the 
same  nature. 

With  regard  to  the  roots,  the  most  common  observa- 
tions appear  to  show  that  they  possess  the  power  of 
selecting  the  proper  mineral  nutriment  for  the  plant 
from  the  matters  presented  to  them.  All  plants  do  not 
thrive  equally  well  in 'the  same  soil ;  one  kind  succeeds 
best  in  soft  water,  another  in  hard  water,  or  water 
abounding  in  lime ;  another  only  on  marshy  ground ; 
many  on  fields  rich  in  carbon  and  carbonic  acid,  such 
as  the  turf-plants  ;  others  again  on  soil  containing  large 
quantities  of  alkaline  earths.  Many  mosses  and  lichens 
will  grow  only  on  stones,  the  surfaces  of  which  they 
sensibly  change  ;  others,  like  Koleria,  possess  the  faculty 
of  extracting  from  silicious  sandstone  potash  and  the 
phosphoric  acid  so  sparingly  present  in  it.  Roots  of 
grass  attack  the  felspar  rocks,  accelerating  their  disin- 
tegration. Rapes  and  turnips,  sanfoin  and  lucerne,  as 
also  the  oak  and  beech,  receive  the»  chief  part  of  their 
food  from  the  subsoil  poor  in  humus  ;  while  the  cereal 
and  tuberous  plants  thrive  best  in  the  arable  surface 
soil,  and  in  soil  abounding  in  humus.  The  roots  of 
many  parasitic  plants  are  absolutely  unable  to  extract 
froni  the  soil  their  necessary  food  ;  but  this  is  prepared 
for  them  by  the  roots  of  the-  plants  on  which  they  grow. 
Others  again,  as  certain  fungi;  grow  only  on  vegetable 
and  animal  remains,  whose  azotised  and  unazotised  sub- 
stances they  use  for  their  own  construction. 

These  facts,  accepted  in  their  true  significance,  seem 
sufficient  to  remove  all  doubt  respecting  the  different 
action  of  the  roots  of  plants  upon  the  soil.  We  know 
that  common  Lycopodium  (club-moss)  and  ferns  absorb 


72  THE   PLANT. 

alumina ;  yet  we  also  know  that  this  substance,  in  the 
form  in  which  it  occurs  in  all  fertile  soils,  is  not  soluble 
in  pure  water,  or  water  containing  carbonic  acid  ;  and 
that  it  cannot  be  detected  in  any  other  plant  growing 
on  the  same  soil  by  the  side  of  the  club-moss.  In  like 
manner,  Schultz-Fleeth  could  not  discover  in  the  water 
in  which  Arundo  phragmites  (one  of  the  plants  most 
abounding  in  silicic  acid)  was  growing,  sufficient  silicic 
acid  to  yield  a  ponderable  amount  in  the  composition 
of  1000  parts  of  the  water. 


CHAPTEK   II. 


THE   SOIL. 

The  soil  contains  the  food  of  plants — Soil  and  subsoil  ,  conversion  of  the  latter  into 
the  former— Power  of  the  soil  to  withdraw  the  food  of  plants  from  solution  in 
pure  and  in  carbonic  acid  water  ;  similar  action  of  charcoal ;  process  of  surface 
attraction  ;  chemical  decomposition  often  accompanies  this  attraction  of  the 
food  of  plants  in  the  soil  ,  general  resemblance  of  the  soil  in  its  action  to  ani- 
mal charcoal — All  arable  soils  possess  the  power  of  absorption,  but  in  different 
degrees — Mode  of  the  distribution  of  the  food  of  plants  in  the  soil ;  chemically 
and  physically  fixed  condition  of  the  food— Only  the  physically  fixed  are  avail- 
able to  plants,  being  made  soluble  by  the  roots — Power  of  the  soil  to  nourish 
plants;  on  what  dependent— Comportment  of  an  exhausted  soil  in  fallow- 
Means  for  making  the  chemically  iixed  elements  of  food  available  to  plants — 
Action  of  air,  weather,  decaying  organic  matters  and  chemical  means— Distri- 
bution of  phosphoric  and  silicic  acids  ;  influence  of  organic  matters— Action  of 
lime— Process  of  the  absorption  of  food  from  the  soil  by  the  extremities  of  the 
roots— Mechanical  preparation  of  the  soil;  its  influence  on  the  growth  of 
plants  ;  chemical  means  for  preparing  the  soil — Rotation  of  crops  ;  its  influ- 
ence on  the  quality  of  the  soil  ;  action  of  draining — Plants  do  not  receive  their 
food  from  a  solution  circulating  in  the  soil;  examination  of  drain  ;  lyseraeter, 
spring  and  river  water  :  bog  water,  food  of  plants  contained  in  it  ;  Bruckenatier 
spring  water  contains  volatile  fatty  acids  ,  amount  of  food  of  plants  in  natural 
waters  dependent  on  the  nature  of  the  soil  through  which  they  flow— Mud  and 
bog  earth  as  manure  ;  explanation  of  their  action— Manner  in  which  plants 
take  up  their  food  from  the  soil  ;  experiments  on  the  growth  of  plants  in  solu- 
tions containing  their  food  ;  similar  experiments  with  soil  containing  the  food 
in  a  physically  fixed  state — Intimate  connection  of  natural  laws — Average 
crop  ;  necessary  quantity  of  assimilable  food  in  the  soil  for  the  production  of 
such  ;  importance  of  the  extent  of  surface  of  the  food  in  the  soil  ;  the  root  sur- 
face—Quantity of  food  for  a  given  surface  of  roots  necessary  for  a  wheat  or 
rye  crop — Analysis  of  the  soil  of  a  field— Difference  between  fertility  and  pro- 
ductive power  of  a  field — Mode  of  estimating  relative  extent  of  root  surfaces 
—Conversion  of  rye  into  wheat  soil ;  quantity  of  food  necessary  for  the  pur- 
pose ;  the  plan  impracticable — Immobility  in  the  soil  of  the  food  of  plants  ;  ex- 
perience in  agriculture— Real  and  ideal  maximum  production— Convers'on  in 
practice  of  the  chemically  fixed  food  into  an  available  form— Effect  of  a  manure 
depends  upon  the  property  of  the  soil — Improper  relative  proportions  of  the 
different  elements  of  food  in  the  so;l  •  effect  of  this  upon  the  different  culti- 
vated plants  ;  means  for  restoring  the  proper  relative  proportions. 

FROM  the  soil  plants  receive  the  food  necessary  for 
their  developement ;  hence  an  acquaintance  with  its 
chemical  and  physical  properties  is  important  in  helping 
us  to  understand  the  nutritive  processes  of  plants,  and 
the  operations  of  agriculture.     As  a  matter  of  course,  a 

4 


74  THE   SOIL, 

soil  to  be  fertile  for  cultivated  plants,  must,  as  a  pri- 
mary condition,  contain  in  sufficient  quantity  the  nutri- 
tive substances  required  by  those  plants.  .But  chem- 
ical analysis,  which  determines  this  relation,  gives  but 
rarely  a  correct  standard  by  which  to  measure  the 
fertility  of  different  soils,  because  the  nutritive  sub- 
stances therein  contained,  to  be  really  available  and 
effective,  must  have  a  certain  form  and  condition,  which 
analysis  reveals  but  imperfectly. 

Rough  uncultivated  ground,  and  soil  formed  from 
the  dust  and  dried  mud  of  the  highroads,  are  speedily 
overgrown  with  weeds,  and  though  often  still  unfit  for 
the  cultivation  of  cereal  and  kitchen  plants,  may  yet 
prove  not  unfruitful  for  other  plants,  requiring,  like 
clover,  sanfoin,  and  lucerne,  a  large  amount  of  food, 
and  which  are  often  seen  thriving  luxuriantly  on  the 
slopes  of  railway  embankments  formed  of  earth  that 
has  never  been  under  cultivation.  A  similar  relation  is 
shown  by  the  subsoil  of  many  fields.  In  many  of  them 
the  earth  from  the  deeper  layers  improves  the  surface 
soil,  and  increases  its  fertility ;  in  others,  the  subsoil 
mixed  with  the  surface  soil  destroys  the  fertility  of  the 
latter. 

It  is  a  remarkable  fact  that  rough  uncultivated  soil, 
unsuited  for  cereal  and  kitchen  plants,  may  by  diligent 
cultivation  during  several  years,  and  by  the  influence 
of  the  weather,  become  fertile  enough  to  produce  those 
plants  which  it  formerly  refused  to  bear.  The  dif- 
ference between  fertile  arable  land  and  barren  untilled 
soil  is  not  the  result  of  any  dissimilarity  in  the  nutritive 
substances  which  they  contain ;  because  in  cultivation 
upon  a  large  scale,  to  convert  the  untilled  rough  soil 
into  fertile  arable  land,  the  ground,  so  far  from  being 
enriched,  is  rather  impoverished  by  the  cultivation  of 
other  plants  on  it. 

The  difference  between  the  subsoil  and  the  arable 
surface  soil,  or  the  crude  and  the  cultivated  soil,  sup- 
posing that  both  contain  the  same  amount  of  nutritive 
substances,  can  only  be  founded  upon  this,  that  the  cul- 
tivated ground  contains  the  nutritive  substances  of 


A    SOIL    WHEN    SAID   TO    BE   FERTILE.  75 

plants,  not  only  in  a  more  uniform  mixture,  but  also  in 
another  form. 

Now  as  from  the  influence  of  cultivation  and  weather 
above-mentioned,  the  rough  soil  acquires  the  power  of 
furnishing  the  elements  of  food  which  it  contains,  in  just 
the  same  quantity  and  in  the  same  time  as  cultivated 
soil,  a  power  which  was  formerly  wanting  in  it  with 
regard  to  certain  plants,  it  cannot  be  denied  that  an 
alteration  must  have  taken  place  in  the  original  form 
and  fashion  of  these  elements. 

Suppose  we  have  a  soil  consisting  of  disintegrated 
rocks  :  in  the  smallest  particles  of  such  a  soil,  the  nutri- 
tive substances  of  plants,  as  potash  for  instance  in  a 
silicate,  are  retained  in  combination  by  the  chemical 
attraction  of  silicic  acid,  alumina,  &c.  This  attraction 
has  to  be  overcome  by  one  still  more  powerful,  if  the 
potash  is  to  be  liberated  and  made  available  for  passing 
into  plants.  If  we  find  that  some  plants  are  perfectly 
developed  in  a  soil  of  the  kind,  which  remains  unfruit- 
ful for  others,  we  are  led  to  assume  that  the  former  are 
able  to  overcome  the  chemical  resistances  opposed  to 
their  growth,  and  that  the  latter  are  not.  Further,  if 
we  find  the  same  soil  gradually  acquiring  the  power  of 
producing  these  latter  plants  also,  we  can  assign  no 
other  reason  than  this,  that  by  the  combined  action  of 
air,  water,  and  carbonic  acid,  aided  by  mechanical 
operations,  the  chemical  resistances  have  been  over- 
come, and  the  alimentary  substances  have  been  reduced 
to  a  form  in  which  they  are  available  for  absorption 
even  by  plants  endowed  with  the  feeblest  powers  of 
vegetation. 

A  soil  can  only  then  be  said  to  be  perfectly  fertile 
for  a  given  species  of  plant,  e.g.  wheat,  when  every  part 
of  its  horizontal  section  which  is  in  contact  with  the 
roots  contains  the  amount  of  food  required  by  the  plant, 
in  a  form  allowing  the  roots  to  absorb  such  food  at  the 
proper  time,  and  in  the  proper  quantity,  during  every 
stage  of  its  developement. 

In  a  former  section  mention  has  been  made  of  a 
property  possessed  by  arable  soil,  viz.  that  when 


76  THE    SOIL. 

brought  into  contact  with  solutions  of  the  articles  of 
food  most  essential  for  plants  in  pure  water  or  in  water 
containing  carbonic  acid,  it  can  withdraw  these  ele- 
ments of  food  from  such  solutions.  This  power  throws 
light  upon  the  form  and  condition  in  which  these  mate- 
rials are  contained  or  combined  in  the  soil. 

To  estimate  this  property  correctly  in  its  bearing 
upon  the  life  plants,  we  must  call  to  mind  a  similar 
property  in  charcoal,  which,  like  arable  soil,  withdraws 
from  many  fluids  colouring  matters,  salts  and  gases. 

This  power  in  charcoal  depends  upon  a  chemical 
attraction  proceeding  from  its  surface,  and  the  materials 
withdrawn  from  the  fluid  adhere  to  the  charcoal  in 
exactly  the  same  way  that  the  colouring  matter  adheres 
to  the  fibre  of  coloured  stuffs  coated  over  with  it. 

The  property  of  decolorising  coloured  fluids,  which 
animal  wood  and  vegetable  fibre  share  in  common  with 
charcoal,  is  perceptible  in  those  kinds  of  charcoal  only 
which  possess  a  certain  degree  of  porosity. 

Powdered  pit  coal,  and  the  shining,  smooth,  blis- 
tered charcoal  from  sugar  or  blood,  have  hardly  any 
decolorising  action  ;  whereas  porous  blood-charcoal  and 
bone-charcoal  with  its  fine  pores  exceed  all  other  varie- 
ties in  this  property. 

Among  the  wood-charcoals,  those  made  from  poplar 
or  pine,  having  wide  pores,  are  inferior  to  the  charcoal 
of  the  beech  and  box  tree  ;  all  these  varieties  decolorise 
in  proportion  to  the  extent  of  surface  which  attracts 
colouring  matter.  The  attractive  force  which  charcoal 
exercises  upon  colouring  matter  is  about  on  a  par  with 
the  feeble  affinity  of  water  for  salts,  which  are  dissolved 
by  it,  but  without  alteration  of  their  chemical  proper- 
ties. When  dissolved  in  water,  a  salt  simply  assumes 
the  fluid  state,  and  its  particles  acquire  mobility ;  but 
in  all  other  respects  it  retains  its  characteristic  proper- 
ties, which,  as  is  well  known,  are  completely  destroyed 
by  the  action  of  a  stronger  affinity  than  that  of  water. 

In  this  respect  the  attraction  of  charcoal  resembles 
that  of  water,  for  both  attract  the  dissolved  matter.  If 
the  attraction  of  the  charcoal  is  somewhat  greater  than 


ABSORPTIVE   POWER   OF   SOILS.  77 

that  of  the  water,  then  the  colouring  matter  is  com- 
pletely withdrawn  from  the  water  ;  if  the  attraction  of 
both  is  equal,  a  division  takes  place,  and  the  attraction 
is  only  partial. 

The  materials  attracted  by  the  charcoal  retain  all 
their  chemical  properties,  and  continue  unaltered,  mere- 
ly losing  their  solubility  in  water ;  yet  very  slight  cir- 
cumstances, increasing  in  the  least  degree  the  attractive 
force  of  the  water,  are  sufficient  again  to  withdraw  from 
the  charcoal  the  materials  absorbed  by  it,  and  which 
simply  coat  its  surface.  By  a  slight  addition  of  alkali 
to  the  water  the  colouring  matter  may  be  discharged 
from  the  charcoal  which  has  been  used  to  decolorise  the 
fluid,  and  by  treatment  with  alcohol,  the  quinine  or 
strychnine  absorbed  by  charcoal  from  a  fluid  may  be 
again  extracted. 

'The  arable  soil  possesses,  in  these  respects,  the  same 
properties  as  charcoals.  Diluted  liquid  manure,  of  deep 
brown  colour  and  strong  smell,  filtered  through  arable 
soil,  flows  off  colourless  and  inodorous  ;  and  not  merely 
does  it  lose  its  smell  and  colour,  but  the  ammonia, 
potash,  and  phosphoric  acid  which  it  holds  in  solution, 
are  also  more  or  less  completely  withdrawn  from  it  by 
the  soil,  and  this  in  a  far  greater  degree  than  by  char- 
coal. The  rocks  which  by  disintegration  give  rise  to 
arable  soil,  if  reduced  to  a  fine  powder,  are  just  as  little 
possessed  of  this  power  as  pounded  coal.  On  the  con- 
trary, contact  with  pure  water  or  water  containing  car- 
bonic acid,  deprives  many  silicates  of  potash,  soda,  and 
other  constituents,  a  clear  proof  that  the  former  cannot 
possibly  withdraw  the  latter  from  the  water.  There  is 
no  perceptible  connection  between  the  composition  of  a 
soil  and  its  power  of  absorbing  potash,  ammonia,  and 
phosphoric  acid.  A  soil  abounding  in  clay,  with  a 
small  proportion  of  lime  ii\it,  possesses  this  absorptive 
power  in  the  same  degree  as  a  lime  soil  with  a  small 
admixture  of  clay ;  but  the  amount  of  humus  substances 
will  alter  the  absorptive  relation. 

By  a  closer  observation  we  perceive  that  the  absorp- 
tive power  of  arable  soil  differs  in  proportion  to  its 


78  THE   SOIL. 

greater  or  less  porosity ;  a  dense,  heavy  clay  soil  and  a 
loose  sandy  soil  possess  the  absorptive  power  in  the 
smallest  degree. 

There  can  be  no  doubt  that  all  the  component  parts 
of  arable  soil  have  a  share  in  these  properties,  but  only 
when  they  possess  a  certain  mechanical  condition,  like 
wood  or  animal  charcoal ;  and  that  this  power  of 
absorption  depends,  as  in  charcoal,  upon  a  surface 
attraction,  which  is  termed  a  physical  attraction,  be- 
cause the  attracted  particles  enter  into  no  chemical 
combination,  but  retain  their  chemical  properties.* 

The  arable  soil  owes  its  formation  to  the  disintegra- 
tion of  minerals  and  rocks,  brought  about  by  the  action 
of  mighty  mechanical  and  chemical  agencies.  Though 
the  comparison  may  not  be  altogether  apt,  the  rock 
may  be  said  to  stand  in  about  the  same  relation  to  the 
arable  soil  resulting  from  its  disintegration  as  the  wood 
or  the  vegetable  fibre  to  the  humus  resulting  from  its 
decay. 

The  same  causes  which  in  the  course  of  a  few  years 
convert  wood  into  humus  act  also  upon  rocks,  with  this 
difference,  however,  that  it  requires  the  combined  action 
of  water,  oxygen,  and  carbonic  acid,  for  probably  a 
thousand  years,  to  produce  from  basalt,  trachyte,  fel- 
spar, or  porphyry,  the  thinnest  layer  of  arable  soil  (such 
as  is  found  in  the  plains  of  river  valleys  and  low  lands) 
with  all  the  chemical  and  physical  properties  suited  for 
the  nutrition  of  plants.  Sawdust  possesses  the  proper- 
ties of  humus  no  more  than  powdered  rocks  have  the 
properties  of  arable  soil.  No  doubt  sawdust  may  pass 
into  humus  and  powdered  stones  into  arable  soil,  but 
the  two  states  are  essentially  distinct ;  and  no  human 
art  can  imitate  the  operations  which  were  necessary, 
during  immense  ages,  to  convert  the  divers  kinds  of 
rocks  into  arable  soil.  , 

Arable  soil,  resulting  from  the  disintegration  of 
various  kinds  of  rocks,  bears  the  same  relation,  in 

*  The  term,  '  physical  attraction,'  as  used  here,  does  not  signify  a 
peculiar  attractive  force,  but  merely  designates  the  ordinary  chemical 
affinity,  which  shows  differences  of  degree  in  its  manifestation. 


ARABLE    SOIL    COMPARED   TO    ANIMAL    CHARCOAL.        79 

respect  of  absorptive  power  for  inorganic  substances  in 
solution,  as  the  woody  fibre  altered  bv  the  action  of 
heat  bears  to  organic  substances  in  solution. 

It  has  been  stated,  that  from  a  solution  of  carbonate 
of  potash  or  ammonia,  or  from  a  solution  of  phosphate 
of  lime  in  carbonic  acid  water,  the  arable  soil  will  with- 
draw the  potash,  ammonia,  and  phosphoric  acid,  with- 
out any  chemical  interchange  with  the  constituents  of 
the  earth  taking  place.  In  this  respect  the  action  of 
arable  soil  is  absolutely  like  that  of  charcoal.  But  it 
goes  farther,  for  it  is  sufficiently  powerful  to  sever  the 
connection  between  the  potash  or  ammonia  and  the 
mineral  acid,  for  which  they  have  the  greatest  affinity, 
the  potash  being  absorbed  by  the  soil  just  as  though  it 
were  not  combined  with  an  acid. 

In  this  property  arable  soil  is  like  animal  charcoal, 
which,  by  means  of  the  phosphates  of  the  alkaline  earths 
contained  in  it,  decomposes  many  salts  that  are  not 
aifected  by  charcoals  free  from  such  phosphates ;  and, 
without  doubt,  the  lime  and  magnesia  compounds  in- 
variably present  in  arable  soil  have  a  share  in  this  de- 
composing power  which  it  possesses. 

We  must  suppose  that  the  attractive  force  of  the 
earthy  particles  would  not  in  itself  be  strong  enough  to 
separate,  for  instance,  potash  from  nitric  acid,  and  that 
it  requires  the  additional  attraction  of  the  lime  or  mag- 
nesia to  decompose  the  nitrate  of  potash.  On  the  one 
side  the  soil  attracts  the  potash,  on  the  other  the  lime 
or  magnesia  in  the  earth  attracts  the  nitric  acid,  and 
thus  the  combined  attraction  effects,  as  in  innumerable 
instances  in  chemistry,  a  separation  which  could  not 
have  been  brought  about  by  a  simple  one. 

The  process  of  decomposition  effected  by  arable  soil 
differs  only  in  one  respect  from  the  ordinary  chemical 
processes,  namely,  that  in  the  latter,  as  a  general  rule, 
no  soluble  potash  salt  is  decomposed  by  an  insoluble 
lime  salt,  in  such  a  manner  that  the  potash  is  thereby 
made  insoluble  and  the  lime  soluble.  There  is  evident- 
ly here  some  other  attractive  force  at  work,  which  alters 
the  effect  of  chemical  affinity.  If  a  solution  of  phos- 


80  THE    SOIL. 

phate  of  lime  in  water  containing  carbonic  acid  is 
filtered  through  a  funnel  filled  with  earth,  the  upper- 
most layer  of  the  earth  first  takes  up  the  phosphoric 
acid  or  the  phosphate  of  lime  from  the  fluid.  Once 
saturated  therewith  it  no  longer  stops  the  free  passage 
of  the  dissolved  phosphate  of  lime  which  now  reaches 
the  layer  beneath  ;  the  latter  then  again  becomes  satu- 
rated in  the  same  way,  and  thus  by  degrees  the  phos- 
phate of  lime  is  completely  diffused  throughout  the 
earth  in  the  funnel,  so  that  every  particle  retains  on  its 
surface  an  equal  proportion  of  this  substance.  If  the 
phosphate  of  lime  were  of  the  colour  of  madder  and  the 
soil  colourless,  the  latter  would  now  actually  present 
the  appearance  of  a  madder  lake.  Just  in  the  same 
way  potash  is  diffused  through  the  soil  when  a  solution 
of  carbonate  of  potash  is  filtered  through  it ;  the  lower 
layers  receive  what  the  upper  do  not  retain. 

There  is  no  need  of  any  special  disquisition  to  show 
that  the  phosphate  of  lime  contained  in  a  particle  of 
bone-earth  is  diffused  in  exactly  the  same  way  through 
arable  soil,  with  this  difference,  that  the  solution  of 
phosphate  of  lime  in  rain-water  containing  carbonic 
acid  is  effected  at  the  very  spot  where  the  particle  lies, 
and  spreads  thence  downward  and  in  all  directions. 

The  potash  and  the  silicic  acid  rendered  soluble  by 
disintegration,  or  by  the  action  of  water  and  carbonic 
acid  upon  silicates,  are  diffused  through  the  soil  in  the 
same  way,  so  is  ammonia  also,  which  is  conveyed  in 
rain-water,  or  is  generated  by  the  putrefaction  of  the 
azotised  constituents  in  the  decayed  roots  from  the  suc- 
cessive generation  of  plants  grown  on  a  field. 

Every  soil  must  therefore  contain  potash,  silicic  acid 
and  phosphoric  acid  in  twp  different  forms,  namely,  in 
chemical  and  ^physical  combination :  in  the  one  form, 
infinitely  diffused  over  all  the  surface  of  the  porous  par- 
ticles of  the  soil ;  in  the  other,  in  the  shape  of  granules 
of  phosphorite,  or  apatite  and  felspar,  very  unequally 
distributed. 

In  a  soil  abounding  in  silicate  and  in  phosphate  of 
lime,  which  has  for  thousands  of  years  been  exposed  to 


FOOD   PHYSICALLY   AND    CHEMICALLY    COMBINED.        81 

the  dissolving  action  of  water  and  carbonic  acid,  the 
component  particles  will  be  found  everywhere  physi- 
cally saturated  with  potash,  ammonia,  silicic  acid,  and 
phosphoric  acid  ;  and  it  may  occur,  as  in  the  case  of  the 
so-called  Russian  black-earth,  that  the  phosphate  of 
lime  dissolved  but  not  absorbed  is  deposited  again  in 
concretions,  or  in  a  crystalline  form  in  the  subsoil. 

In  this  state  of  physical  combination  the  alimentary 
substances  are  manifestly  in  the  most  favourable  condi- 
tion to  serve  as  food  for  plants;  for  it  is  clear  that  the 
roots,  in  all  places  where  they  are  in  contact  with  the 
soil,  will  find  the  necessary  nutritive  substances  in  the 
same  state  of  diffusion  and  readiness  as  if  these  substan- 
ces were  in  solution  in  water,  but  at  the  same  time  not 
movable  of  themselves,  and  retained  in  the  soil  by  so 
slight  a  force  that  the  most  trifling  dissolvent  cause 
brought  to  bear  upon  them  suffices  to  effect  their  solu- 
tion and  transition  into  the  plant. 

If  it  is  true  that  the  roots  of  cultivated  plants  have 
no  inherent  power  to  overcome  the  force  which  retains 
together  potash  and  silicic  acid  in  the  silicates,  but  that 
those  elements  of  food  only  which  are  in  physical  com- 
bination with  the  soil  can  be  taken  up  and  made  avail- 
able for  nutriment,  this  explains  the  difference  between 
cultivated  and  uncultivated  ground,  or  barren  sub- 
soil. 

Nothing  can  be  more  certain  than  that  the  mechan- 
ical treatment  of  the  soil  and  the  influence  of  the 
weather  serve  to  strengthen  the  causes  which  bring 
about  the  disintegration  and  decomposition  of  the 
minerals,  and  the  uniform  distribution  of  the  elements 
of  food  contained  in  them  and  rendered  soluble.  The 
elements  chemically  combined  in  the  minerals,  are  re- 
leased from  that  combination,  and  in  the  arable  S'oil 
gradually  resulting  from  this  decomposition  acquire  the 
form  in  which  they  are  available  as  food  for  plants.  It 
is  evident  that  only  by  degrees  the  rough  ground  can 
attain  the  properties  of  arable  soil,  and  that  the  time 
required  for  this  change  depends  upon  the  quantity  of 
nutritive  substances  present,  and  upon  the  obstacles 


82  THE   SOIL. 

which  oppose  their  distribution,  or  their  disintegration 
and  decomposition.  The  perennial  plants,  and  particu- 
larly the  so-called  weeds,  consuming  in  proportion  to 
the  time  less  food,  and  absorbing  longer,  will  always 
thrive  on  a  soil  of  this  description  long  before  annual 
or  summer  plants,  which  in  their  shorter  period  of 
vegetation  require  a  far  larger  amount  of  nutritive  sub- 
stances for  their  full  development. 

The  longer  a  soil  is  under  cultivation,  the  more  it 
becomes  suited  for  the  growth  of  summer  plants,  from 
the  recurrence  and  operation  of  the  causes  by  which 
the  nutritive  substances  are  converted  from  a  state  of 
chemical  into  one  of  physical  combination.  To  be  pro- 
ductive, in  the  fullest  sense  of  the  term,  a  soil  must  be 
able  to  afford  food  at  all  points  in  contact  with  the  roots 
of  the  plants ;  and,  however  small  the  quantity  of  this 
food  may  be,  it  must  necessarily  be  distributed  through 
every  part  of  the  soil. 

The  power  of  the  soil  to  nourish  cultivated  plants  is 
therefore  in  exact  proportion  to  the  quantity  of  nutritive 
substances  which  it  contains  in  a  state  of  physical  satii- 
ration.  The  quantity  of  the  other  elements  in  a  state 
of  chemical  combination  distributed  through  the  ground 
is  also  highly  important,  as  serving  to  restore  the  state 
of  saturation  when  the  nutritive  substances  in  physical 
combination  have  been  withdrawn  from  the  soil  by  a 
series  of  crops  reaped  from  it. 

Experience  proves  that  the  cultivation  of  deep-root- 
ing plants,  which  draw  their  food  principally  from  the 
subsoil,  does  not  materially  impair  the  fertility  of  the 
surface  soil  for  a  succeeding  crop  of  cereal  plants ;  but 
the  successive  cultivation  of  the  latter  will,  in  a  com- 
paratively small  number  of  years,  render  the  soil  incapa- 
ble of  yielding  a  remunerative  crop. 

With  most  of  our  cultivated  fields  this  state  of  ex- 
haustion is  not  permanent.  If  the  ground  is  left  fallow 
for  one  or  more  years,  especially  if  it  is  well  ploughed 
and  harrowed  during  the  time,  it  recovers  the  power  of 
yielding  a  remunerative  crop  of  cereal  plants. 

Chemical  analysis  leaves  altogether  unexplained  the 


FOOD   PHYSICALLY    COMBINED.  83 

causes  of  this  fact,  so  highly  important  to  agriculture, 
and  which  has  been  fully  established  by  the  experience 
of  several  thousand  years.  If  the  reason  be  that  cereal 
plants  feed  011  those  substances  only  which  are  in  physi- 
cal combination  in  the  surface  soil,  then  we  can  easily 
understand  the  remarkable  fact  of  a  field  recovering  its 
power  of  production  without  any  supply  of  manure ;  for 
though  the  nutriment  in  this  form  constitutes  but  a 
small  portion  of  the  soil  by  weight,  yet  it  imparts  nutri- 
tive qualities  to  a  large  volume  of  it ;  and  it  is  quite 
intelligible  that  a  soil  not  originally  rich  in  nutritive 
substances  physically  combined,  when  drained  of  them 
by  the  innumerable  underground  absorptive  organs  of 
a  plant,  must  very  speedily  become  unsuited  lor  the 
cultivation  of  that  plant. 

Now  as  the  cultivated  soil  is  composed  in  the  main 
of  ingredients  which  are  identical  with  the  constituents 
of  uncultivated  ground,  and  as  the  agencies  affecting 
the  decomposition  of  these  ingredients,  and  the  trans- 
position of  their  constituents  affording  food  to  plants 
are  in  constant  operation,  it  is  easy  to  conceive  how,  by 
the  influence  of  such  causes,  an  exhausted  soil,  which  is 
in  fact  nothing  else  than  a  soil  reduced  to  its  crude  state 
previous  to  cultivation,  must  regain  the  properties 
which  it  had  lost.  With  the  conversion  of  a  fresh  por- 
tion of  the  food  elements  from  a  state  of  chemical  to 
one  of  physical  combination,  the  field  recovers  the 
power  of  affording  food  to  a  fresh  vegetation  in  such 
quantity  that  the  crops  are  again  remunerative  to  the 
agriculturist. 

An  exhausted  field  which  is  again  rendered  produc- 
tive by  fallowing,  may  accordingly  be  defined  as  land 
deficient  in  physically  combined  nutritive  substances 
necessary  for  a  full  crop,  while  containing  an  excess  of 
such  substances  in  a  chemically  combined  state.  The 
fallowing  season,  therefore,  means  the  time  in  which 
the  nutritive  substances  pass  over  from  the  one  state  to 
the  other.  It  is  not  the  amount  of  nutritive  substances 
that  is  increased  in  fallowing,  but  the  number  of  parti- 
cles of  their  constituents  capable  of  affording  nutrition. 


84  THE   SOIL. 

"What  is  here  asserted  of  all  the  mineral  nutritive 
substances  without  distinction  applies  equally  to  every 
soil  constituent  required  by  the  plant.  The  exhaustion 
of  a  field  may  often  simply  depend  upon  a  deficiency  of 
available  silicic  acid  for  the  coming  crop  of  cereal 
plants,  while  the  other  food  elements  may  be  super- 
abundant. 

It  is  evident  from  the  nature  of  the  process,  that  if 
the  soil  is  altogether  deficient  in  disintegrate  silicates 
or  soluble  earthy  phosphates,  the  action  of  time,  the 
plough,  and  the  weather  in  fallow  will  not  restore  fer- 
tility to  a  field,  and  that  the  effect  of  disintegrating 
causes  will  vary  with  the  time  they  are  in  operation, 
and  with  the  composition  of  the  different  soils. 

It  clearly  results  from  the  foregoing  observations, 
that  one  of  the  principal  requirements  of  the  practical 
farmer  is  to  know  the  causes  as  well  as  the  means 
whereby  the  useful  nutritive  substances  present  in  his 
field,  but  not  in  a  form  available  for  nutrition,  may  be 
rendered  diffusible  and  capable  of  doing  their  wrork. 

The  presence  of  moisture,  a  certain  degree  of  heat, 
and  free  access  of  air,  are  the  proximate  conditions  of 
those  changes  by  which  the  nutritive  substances  in 
chemical  combination  are  made  available  for  the  roots. 
A  certain  quantity  of  water  is  indispensable  to  trans- 
pose the  soil-constituents  when  rendered  soluble ; 
water,  with  the  co-operation  of  carbonic  acid,  decom- 
poses the  silicates,  and  makes  the  undissolved  phos- 
phates soluble  and  diffusible  through  the  soil. 

The  organic  remains  decaying  in  the  ground  afford 
feeble  but  long-continued  sources  of  carbonic  acid  ;  but 
without  moisture  no  process  of  decay  can  take  place. 
Stagnant  water,  again,  which  excludes  the  access  of  air, 
prevents  the  generation  of  carbonic  acid ;  and  the  pro- 
cess of  putrefaction  is  attended  with  the  generation  of 
heat,  whereby  the  temperature  of  the  soil  is  perceptibly 
increased. 

By  the  aid  of  putrescent  vegetable  and  animal  re- 
mains, a  field  exhausted  by  culture  will  regain  its  fer- 
tility in  a  shorter  time,  and  the  use  of  farm-yard 


CONDITIONS    FOE    KENDEEING   FOOD   AVAILABLE.          85 

manure  in  time  of  fallow  will  promote  the  process. 
The  dense  shadow  cast  by  a  leafy  plant  tends  to  retain 
moisture  longer  in  the  ground,  and  thus  increases  the 
action  of  the  disintegrating  agencies  during  the  fallow 
season. 

In  a  porous  soil  abounding  in  lime  the  putrefactive 
process  of  organic  matter  proceeds  much  more  quickly 
than  in  a  clay  soil ;  the  presence  of  the  alkaline  earth, 
under  these  circumstances,  serving  to  oxidise  the  car- 
bonaceous matter,  and  to  convert  the  ammonia  present 
in  the  soil  into  nitric  acid. 

All  kinds  of  lime,  when  lixiviated,  give  up  nitrates 
to  the  water.  Nitric  acid  is  not  retained  by  the  porous 
earth,  as  is  ammonia ;  but  it  is  carried  down  combined 
with  lime  or  magnesia  by  the  rain-water  into  the 
deeper  layers  of  the  soil.  While  the  formation  of  nitric 
acid  taking  place  in  the  ground  is  useful  for  plants 
which,  like  clover  and  peas,  draw  their  food  (here  in- 
cluding nitrogen)  from  a  greater  depth,  yet  for  this 
very  reason  fallowing  has  a  less  beneficial  eifect,  with  a 
view  to  the  culture  of  cereal  plants,  upon  a  lime  soil 
rich  in  animal  remains ;  for  by  the  conversion  of  am- 
monia into  nitric  acid,  and  its  removal,  the  ground  be- 
comes poorer  in  one  of  the  most  important  elements  of 
the  food  of  plants.  The  case  is  conceivable  that  a  field 
of  the  kind,  if  not  cultivated  for  a  number  of  years,  may 
ultimately  have  its  productive  powers  impaired  by  a 
deficiency  of  nitrogenous  food  in  the  soil. 

The  cause  of  the  exhaustion  of  a  field  by  the  culture 
of  any  plant  is  always,  and  under  all  circumstances, 
dependent  upon  a  deficiency  of  one  or  more  nutritive 
substances  in  those  portions  of  the  soil  which  are  in 
contact  with  the  roots.  A  field  in  which  these  portions 
are  deficient  in  phosphoric  acid  in  the  state  of  physical 
combination,  will  be  found  unsuited  for  the  production 
of  a  proper  crop,  though  it  should  contain  abundance 
of  available  potash  and  silicic  acid.  The  same  results 
will  follow  from  a  want  of  potash,  even  though  phos- 
phoric and  silicic  acids  be  plentiful ;  and  equally  so 
from  a  want  of  silicic  acid,  lime,  magnesia,  or  iron, 


86  THE   SOIL. 

even  where  potash  and  phosphoric  acid  are  in  abund- 
ance. 

When  the  exhaustion  of  a  field  is  not  caused  by  the 
absolute  deficiency  of  food  elements,  when  even  a 
more  than  adequate  supply  of  all  the  needful  nutriment 
is  there,  but  not  in  the  proper  form,  and  where  conse- 
quently fallowing  will  again  render  the  crop  remuner- 
ative, the  farmer  has  means  at  his  disposal  to  assist  the 
action  of  the  natural  agencies,  whereby  the  conversion 
of  the  food  elements  into  the  state  of  physical  combina- 
ation  is  effected,  and  thus  to  shorten  the  fallowing 
season,  or  even  in  many  instances  to  make  it  altogether 
superfluous. 

We  have  seen  that  the  diffusion  of  earthy  phos- 
phates through  the  soil  is  effected  exclusively  by  water, 
which,  if  containing  a  certain  amount  of  carbonic  acid, 
dissolves  these  earthy  salts." 

Now,  there  are  certain  salts,  such  as  chloride  of 
sodium,  nitrate  of  soda,  and  salts  of  ammonia,  which 
experience  has  proved  to  exercise,  under  certain  condi- 
tions, a  favourable  action  upon  the  productiveness  of  a 
field. 

These  salts,  even  in  their  most  dilute  solutions,  pos- 
sess, like  carbonic  acid,  the  remarkable  power  of  dis- 
solving phosphate  of  lime  and  phosphate  of  magnesia ; 
and  when  such  solutions  are  filtered  through  arable 
soil,  they  behave  just  like  the  solution  of  these  phos- 
phates in  carbonic  acid  water.  The  earth  extracts  from 
these  salt  solutions  the  dissolved  earthy  phosphates,  and 
combines  with  the  latter. 

Upon  arable  soil  mixed  with  earthy  phosphates  in 
excess,  these  salt  solutions  act  in  the  same  way  as  upon 
earthy  phosphates  in  the  unmixed  state,  that  is,  they 
dissolve  a  certain  proportion  of  the  phosphates. 

Nitrate  of  soda  and  chloride  of  sodium  suffer,  by 
the  action  of  arable  soil,  a  similar  decomposition  to 
that  of  the  salts  of  potash.  Soda  is  absorbed  by  the 
soil,,  and  in  its  stead  lime  or  magnesia  .enters  into  solu- 
tion in  combination  with  the  acid. 

If  we  compare  the  action  of  arable  soil  upon  salts 


MEANS    FOE   CAUSING   THE   DIFFUSION    OF   FOOD.          87 

of  potash  and  salts  of  soda,  we  find  that  the  soil  has 
far  less  attraction  for  soda  than  for  potash;  so  that 
the  same  volume  of  earth  which  will  suffice  to  remove 
all  the  potash  from  a  solution  will,  in  a  solution  of 
chloride  of  sodium  or  nitrate  of  soda  of  the  same  alka- 
line strength,  leave  undecomposed  three-fourths  of  the 
dissolved  chloride  of  sodium  and  half  of  the  nitrate  of 
soda. 

If,  therefore,  a  field  exhausted  by  culture,  which 
contains  earthy  phosphate  scattered  here  and  there,  is 
manured  with  nitrate  of  soda  or  chloride  of  sodium, 
and  by  the  action  of  rain  a  dilute  solution  of  these  salts 
is  formed,  a  portion  of  them  will  remain  undecomposed 
in  the  ground,  and  must  in  the  moist  soil  exert  an  in- 
fluence, weak  in  itself,  but  sure  to  tell  in  the  long  run. 

Like  carbonic  acid  generated  by  the  putrefaction  of 
vegetable  and  animal  substances,  and  dissolving  in 
water,  these  salt  solutions  become  charged  with  earthy 
phosphates  in  all  places  where  these  occur.  Now 
when  these  phosphates  diffused  through  the  fluid  come 
into  contact  with  particles  of  the  arable  soil  not  already 
saturated  with  them,  they  are  thereby  withdrawn  from, 
.the  solution,  and  the  nitrate  of  soda  or  chloride  of 
sodium  remaining  in  solution  again  acquires  the  power 
of  repeatedly  exerting  the  same  dissolving  and  diffusing 
action  upon  phosphates  which  are  not  already  fixed  in 
the  soil  by  physical  attraction,  until  these  salts  are 
finally  carried  down  by  rain-water  to  the  deeper  layers 
of  the  soil,  or  are  totally  decomposed. 

It  is  well  known  that  chloride  of  sodium  is  present 
in  the  blood  of  all  animals,  and  that  it  plays  a  part  in 
the  processes  of  absorption  and  secretion  ;  hence  it  may 
be  regarded  as  indispensable  for  these  functions.  "We 
find  also  that  nature  has  endowed  fodder-plants,  tuber- 
ous and  root-plants,  which  serve  more  particularly  as 
food  for  cattle,  with  a  greater  power  of  taking  up 
chloride  of  sodium  from  the  soil  than  is  possessed  by 
other  plants ;  and  agricultural  experience  shows  that 
the  presence  of  a  small  amount  of  common  salt  is 
favourable  to  the  luxuriant  growth  of  these  plants. 


88  THE    SOIL. 

Of  nitric  acid,  it  is  generally  assumed  that  it  may, 
like  ammonia,  serve  to  sustain  the  body  of  the  plant. 
Thus,  chloride  of  sodium  and  the  nitrates  act  in  two 
distinct  ways :  one  direct,  by  serving  as  food  for  the 
plant ;  one  indirect,  by  rendering  the  phosphates  avail- 
able for  the  purposes  of  nutrition. 

The  salts  of  ammonia  act  upon  earthy  phosphates 
in  the  same  way  as  the  salts  just  mentioned,  but  with 
this  distinction,  that  their  power  of  dissolving  phos- 
phates is  far  greater ;  a  solution  of  sulphate  of  ammo- 
nia will  dissolve  twice  as  much  bone-earth  as  a  solution 
of  an  equal  quantity  of  chloride  of  sodium. 

However,  as  regards  the  phosphates  in  the  soil,  the 
action  of  the  salts  of  ammonia  can  hardly  be  more 
powerful  than  that  of  chloride  of  sodium  or  nitrate  of 
soda,  since  the  salts  of  ammonia  are  decomposed  by  the 
soil  much  more  speedily,  and  often  even  immediately ; 
so  that,  as  a  general  rule,  no  solution  of  such  a  salt  can 
be  said  to  be  actually  moving  about  in  the  soil.  But 
as  a  certain  volume  of  earth,  however  small,  is  required 
to  decompose  a  given  quantity  of  salts  of  ammonia,  the 
action  of  those  salts  upon  this  small  volume  of  earth 
must  be  all  the  more  powerful.  "While,  then,  the 
action  of  salts  of  ammonia  is  barely  perceptible  in 
the  somewhat  deeper  layers  of  the  arable  surface  soil, 
that  which  they  exercise  on  the  uppermost  layers  is  so 
much  the  stronger.  Feichtinger  observed  that  solu- 
tions of  salts  of  ammonia  decompose  many  silicates, 
even  felspar,  and  take  up  potash  from  the  latter.  Thus, 
by  their  contact  with  the  arable  soil,  they  not  only 
enrich  it  with  ammonia,  but  they  effect,  even  in  its 
minutest  particles,  a  thorough  transposition  of  the  nu- 
tritive substances  required  by  plants. 

The  vegetable  and  animal  remains  in  a  soil  seem  to 
exercise  a  remarkable  influence  upon  the  diffusion  of 
silicates.  The  experiments  made  on  this  point  show 
that  the  absorptive  power  of  an  arable  soil  for  silicic 
acid  is  in  an  inverse  ratio  to  the  amount  of  organic  re- 
mains in  it ;  so  that  a  soil  rich  in  such  remains  will, 
when  brought  into  contact  with  a  solution  of  silicate  of 


DEFICIENCY   OR   EXCESS    OF   SOLUBLE    SILICIC   ACID.       89 

potash,  leave  a  certain  amount  of  silicic  acid  unabsorbed, 
whereas  an  equal  bulk  of  soil  poor  in  organic  remains 
will  take  up  the  whole  of  the  silicic  acid  in  the  solution. 
The  incorporation  of  decaying  vegetable  and  animal 
matter  will,  therefore,  in  a  soil  containing  disintegrable 
silicates,  first  of  all  accelerate  the  decomposition  of  the 
silicates,  by  the  action  of  the  carbonic  acid  generated  in 
the  process  of  de.cay,  and  then  as  these  substances 
diminish  the  absorptive  power  of  the  soil  for  silicic  acid, 
as  soon  as  this  acid  has  passed  into  solution,  it  is  dis- 
tributed through  the  soil  more  widely  than  would  have 
been  the  case  had  these  substances  not  been  present. 

On  many  fields  poor  in  clay,  the  growth  of  grass 
for  several  years  will,  in  consequence  of  the  organic 
matters  collecting  in  the  soil,  which  serve  to  promote 
the  distribution  of  the  silicic  acid,  act  more  favourably 
on  a  succeeding  crop  of  a  cereal  plant  than  a  plentiful 
application  of  farm-yard  manure,  whose  organic  con- 
stituents, quite  irrespective  of  the  silicate  of  potash  in 
the  straw,  are  always  in  operation  to  effect  the  same 
object.  On  many  other  fields,  especially  on  those 
abounding  in  lime,  where  there  is  no  actual  deficiency 
of  silicic  acid,  but  the  quantity  present  is  not  properly 
distributed  through  the  soil,  a  dressing  of  pulverised 
turf-waste  often  produces  an  equally  favourable  effect 
on  a  succeeding  cereal  crop  as  a  plentiful  application 
of  farm-yard  manure. 

Deficiency  or  excess  of  soluble  silicic  acid  in  the 
ground  is  equally  injurious  to  the  growth  of  cereal 
plants.  A  soil  which  would  answer  very  wrell  for 
horse-tail  or  common  reed  (Arundo  phragmites,  plants 
abounding  in  silica)  is  not  on  that  account  equally  well 
suited  for  the  superior  kinds  of  meadow  grass,  or  for 
cereals,  although  these  demand  a  rich  supply  of  silicic 
acid.  Such  a  soil  may  be  improved  by  drainage, 
which,  by  giving  free  access  to  air,  decomposes  and 
destroys  the  organic  substances  present  in  excessive 
quantity  ;  or  it  may  derive  benefit  from  a  dressing  of 
marl,  or  of  burnt  lime,  slaked,  or  fallen  to  powder  by 
moist  air. 


90  .        THE   SOIL. 

Hydrated  silicic  acid  loses  its  solubility  in  water  by 
simple  drying,  and  it  frequently  happens  that  the 
drainage  of  a  marshy  field  will  cause  the  siliceous  plants 
(reeds  and  horsetail)  to  disappear.  The  action  exerted 
upon  the  soil  by  hydrate  of  lime,  or  by  lime  slaked  or 
fallen  to  powder  in  the  air,  is  twofold.  On  a  soil  rich 
in  humus  constituents  the  lime  combines,  in  the  first 
place,  with  the  organic  compounds  present,  which  have 
an  acid  reaction ;  it  neutralises  the  acid  of  the  soil, 
thereby  causing  the  speedy  disappearance  of  many 
weeds,  such  as  bog-moss  (S-phagnum}  and  reed-grasses, 
which  flourish  in  a  sour  soil  of  this  kind.  Simple  con- 
tact with  acids  powerfully  promotes  the  oxidation  of 
metals  (copper,  lead,  iron),  while  contact  with  an  alkali 
prevents  it  (iron  coated  with  a  dilute  solution  of  carbon- 
ate of  soda  will  not  rust).  Upon  organic  substances, 
the  action  is  the  very  reverse:  acids  prevent,  and 
alkalis  promote,  oxidation  or  decay.  Excess  of  lime 
causes  the  aforesaid  destruction  of  the  humose  con- 
stituents. 

In  the  same  degree  as  the  acid  humus,  by  the  action 
of  lime,  disappears  from  the  ground,  the  absorptive 
power  of  the  latter  for  hydrated  silicic  acid  is  increased ; 
and  the  excess  of  this  acid  present  loses  its  mobility  in 
the  soil.* 

The  action  of  lime,  as  we  see,  is  so  complex,  that 
from  its  favourable  influence  upon  one  field,  it  is 
scarcely  ever  possible  to  form  an  opinion  of  its  probable 
action  upon  another  field,  the  condition  of  which  is 
unknown.  This  is  possible  only  when  the  causes  of  its 
favourable  action  in  the  first  case  are  clearly  understood. 

"When  lime  has  improved  the  condition  of  a  field, 
simply  by  neutralising  the  acid  state  of  the  soil,  and 

*  In  an  experiment  made  specially  for  the  purpose,  it  was  found  that  a 
litre  (about  a  quart)  of  forest  soil,  containing  SO  per  cent,  of  humose  con- 
stituents, absorbed  from  a  solution  of  silicate  of  potash  only  15  milli- 
grammes of  silicic  acid.  But  the  same  soil  mixed  with  10  per  cent,  of 
washed  chalk  (carbonate  of  lime)  absorbed  1140  milligrammes;  and  when 
mixed  with  10  per  cent,  of  slaked  lime  instead  of  chalk,  the  absorptive 
power  was  increased  to  such  a  degree,  that  a  litre  absorbed  3169  milli- 
grammes of  silicic  acid. 


BENEFICIAL   ACTION   OF   LIME.  91 

destroying  the  injurious  excess  of  vegetable  remains,  the 
farmer  will  in  vain  expect  a  favourable  result  from  the 
application  of  lime  in  the  following  years,  unless  the 
same  causes  should  recur  which  had  originally  impaired 
the  fertility  of  the  field. 

In  a  soil  wherein  there  are  putrescent  and  decaying 
substances  not  a  single  plant  will  thrive,  except  mush- 
rooms ;  and  it  seems  that  every  chemical  process  going 
on  in  the  neighbourhood  of  roots  disturbs  that  of  their 
own.  Decaying  substances  in  excess,  by  generating 
too  much  carbonic  acid,  injure  even  those  plants  which 
thrive  particularly  well  in  a  humose  soil  containing  a 
moderate  quantity  of  humus. "x" 

Upon  deep-rooting  plants,  such  as  turnips,  clever, 
sanfoin,  peas  and  beans,  organic  matters  accumulating 
largely  in  the  subsoil  act  very  injuriously,  especially  in 
clay,  where '  they  decay  much  more  slowly  than  in  a 
lime  soil.  The  process  of  decay  is  communicated  to  the 
sickening  roots,  in  which  spores  of  fungi  find  a  suitable 
soil  for  their  developement.  When  turnips  are  thus 
affected,  they  become  the  prey  of  certain  insects,  which 
deposit  their  eggs  in  the  roots,  causing  in  their  develope- 
ment a  strange  alteration  and  disturbance  of  the  vege- 
table process  ;  for  in  the  diseased  parts  spongy  tmuours 
arise,  the  inner  substance  of  which  becomes  soft  and 
emits  a  bad  smell,  and  in  this  state  serves  to  nourish 
the  larva  of  the  small  fly. 

All  these  processes,  however  obscure  in  themselves, 
are  put  an  end  to  by  applying  lime  to  such  a  field ;  a 
proper  lime  dressing  will  always  attain  this  object. 
Fields  that  are  particularly  rich  in  organic  remains 

*  Gasparini  sowed  a  few  grains  of  spelt  in  a  pot  with  washed  earth 
from  Vesuvius;  these  produced  plants  which  continued  to  grow  in  a 
healthy  state.  In  another  pot,  filled  with  the  same  earth,  he  introduced  a 
piece  of  bread ;  in  this,  all  the  roots  in  the  immediate  vicinity  of  the 
mouldering  bread  died  away,  and  the  other  roots  seemed  to  have  turned 
off  towards  the  sides  of  the  pot.  It  is  clear  that  spelt  would  not  grow  in  a 
soil  copiously  mixed  with  bread ;  and  if  the  decaying  roots  left  by  a  spelt 
crop  have  the  same  effect,  it  is  not  difficult  to  conceive  how  the  decaying 
remains  which  a  plant  leaves  in  the  ground,  may  injuriously  affect  its  own 
growth,  or  that  of  other  plants.  (Russell.) 


92  THE    SOIL. 

require  a  much  larger  supply  of  lime  than  others,  to 
effect  their  restoration  to  a  healthy  state. 

It  is  certain,  that  in  all  such  cases,  the  beneficial 
action  of  the  lime  is  not  attributable  to  an  original 
deficiency  of  that  body  in  the  soil  for  plants  growing  on 
it ;  for  in  that  case,  considering  the  rapidity  with  which 
ft  is  diffused  through  the  soil,  the  effect  would  manifest 
itself  very  soon,  and  even  in  the  course  of  the  first  year. 
But  it  takes  several  years  before  the  favourable  change 
in  the  condition  of  the  soil  is  effected  ;  proving  that  the 
lime  operates,  not  simply  as  food,  but  by  producing  an 
alteration  in  the  soil,  which  requires  time,  that  is,  a 
succession  of  operations. 

Qn  a  drained  marshy  soil,  in  which  lime  has  dimin- 
ished the  excess  of  hydrated  silicic  acid,  a  second  appli- 
cation will  not  produce  the  same  result,  because  the 
offensive  substances,  once  removed,  -will  not  return; 
while  on  a  heavy,  stiff  clay  or  .loam,  the  application 
may  be  repeatedly  successful.  These  kinds  of  soil  are 
thereby  made  more  friable  and  richer  in  available 
potash.  The  nature  of  the  change  produced  is  most 
clearly  shown  in  the  hydraulic  lime  obtained  by  cal- 
cining native  cement  stones  (a  hard  marl).  These 
cement-stones  consist  of  a  mixture  of  lime  and  clay,  the 
former  being  in  larger  proportion  than  in  calcareous 
clay  soil.  After  burning,  if  it  is  stirred  up  with  a  large 
quantity  of  water,  the  separated  potash  imparts  to  the 
fluid  all  the  properties  of  a  weak  lye.  Clay  which 
before  calcination  with  lime  refused  to  dissolve  in 
acids,  is,  after  calcination,  soluble  in  acids  to  the  whole 
extent  of  the  silicic  acid  present. 

A  calcareous  clay  soil  withdraws  from  a  solution  of 
silicate  of  potash  much  less  potash  after  calcination  than 
before,  but  a  much  larger  quantity  of  silicic  acid.* 

Besides  the  chemical  agents  mentioned  here,  which 

*  At  Bogenhausen,  near  Munich,  loam  was  calcined  in  the  air,  and 
brought  into  contact  with  a  solution  of  silicate  of  potash  ;  before  calcina- 
tion, a  litre  of  this  earth  took  up  1148  milligrammes  of  potash,  and  2007 
milligrammes  of  silicic  acid;  after  calcination,  no  potash,  and  3230  milli- 
grammes of  silicic  acid. 


THE  BOOT  GOES  IN  SEARCH  OF  FOOD.        93 

the  farmer  may  employ  to  effect  the  proper  distribution 
of  the  nutritive  substances  stored  up  in  his  field,  and  to 
make  the  earthy  phosphates,  the  potash,  and  the  silicic 
acid  available  to  the  roots  of  the  plants,  he  further  im- 
proves his  land  by  the  mechanical  operations  of  agricul- 
ture, and  by  removing  from  the  soil  all  obstacles  that 
hinder  the  spreading  of  the  roots,  as  well  as  those  in- 
jurious agencies  which  interfere  with  their  normal  ac- 
tivity, or  endanger  their  healthy  condition. 

the  effect  produced  by  breaking  up  the  ground  by 
the  plough,  spade,  hoe,  harrow,  and  roller,  depends 
upon  the  fact,  that  the  roots  of  plants  go  in  search  of 
their  food ;  that  the  nutritive  substances  have  no  loco- 
motion of  their  own,  and  cannot  of  themselves  leave 
the  place  in  which  they  are.  The  root,  as  if  it  had  eyes 
to  see,  bends  and  stretches  in  the  direction  of  the  nutri- 
ment ;  so  that  the  number,  thickness,  and  direction  of 
its  filaments  indicate  the  precise  spots  where  they  have 
obtained  food.* 

The  young  root  forces  its  way,  not  like  a  nail  driven 
with  a  certain  force  into  a  plank,  but  by  the  addition 
.of  successive  layers,  which  increase  its  mass  from  within 
outwards. 

The  new  substance,  which  lengthens  the  extremity 
of  the  root,  is  in  contact  with  the  soil.  The  newer  the 
cells  forming  at  the  extremities,  the  thinner  are  their 
walls  ;  as  they  grow  older,  the  cell-walls  thicken,  arid 
their  outer  surface,  becoming  more  woody,  is  coated  in 
many  cases  with  a  layer  of  corky  substance,  which, 
being  impenetrable  by  water,  affords,  to  the  soluble 
matter  deposited  within,  some  protection  against  os- 
motic influences. 

*  Pieces  of  bone  are  often  found  completely  enclosed  by  a  network  of 
turnip-roots.  It  is  difficult  to  understand  how  this  could  have  been  accom- 
plished otherwise  than  by  an  attraction  between  the  spongioles  and  the 
substance  of  the  bone.  The  cells,  or  their  contents,  are  incessantly 
attracted  by  the  fresh  surface  of  a  substance,  for  which  the  contents  have 
a  chemical  attraction. 

It  is  owing  to  this  attraction  that  the  roots  wind  round  the  piece  of 
bone ;  they  form  a  root-ball  rolled,  not  from  without,  but  from  within,  by 
the  new  cells  constantly  formed  upon  contact  with  a  substance  for  which 
they  possess  a  chemical  attraction.  (Russell.) 


94  ,  THE    SOIL. 

Absorption  of  nutriment  from  the  soil  is  effected  by 
the  extremities  of  the  roots,  whose  fluid  contents  are 
separated  from  the  earthy  particles  around  them  by  an 
exceedingly  thin  membrane  alone ;  and  the  contact  of 
the  two  is  the  more  intimate,  as  the  root-fibre  during 
its  formation  exerts  upon  the  earthy  particles  a  pres- 
sure sufficiently  powerful,  under  certain  circumstances, 
to  push  them  aside.  The  evaporation  of  water  from  the 
leaves  produces  a  vacuum  within  the  plant,  whereby  a 
draught  is  created,  which  powerfully  assists  the  con- 
tact of  the  moist  earthy  particles  with  the  cell-wall. 
The  cell  and  the  earth  are  pressed  against  each  other. 
Between  the  fluid  contents  of  the  cells  and  the  nutritive 
substances  physically  combined  in  the  earthy  particles, 
there  manifestly  exists  a  strong  chemical  attraction, 
which,  with  the  cooperation  of  carbonic  acid  and  water, 
causes  the  transference  of  the  incombustible  matters 
into  the  system  of  the  plant. 

By  the  powerful  chemical  attraction  of  any  body, 
we  understand  its  entering  into  a  chemical  combination, 
in  which  it  loses  its  original  properties  and  acquires 
new  ones.  In  the  case  of  potash,  lime,  and  phosphoric 
acid,  such  a  combination  must  take  place  immediately 
upoii  their  passage  into  the  cell ;  for,  as  already  stated, 
the  sap  of  the  roots  is  always  slightly  acid.  In.  the  sap 
of  the  root-shoots  of  the  vine,  we  can  always  detect 
bitartrate  of  potash  ;  in  that  of  others,  oxalate  or  citrate 
of  potash,  or  tartrate  of  lime ;  but  we  never  find  these 
bases  combined  in  such  saps  with  carbonic  acid,  nor 
can  phosphate  of  lime  or  magnesia  be  detected.  If  the 
fresh  sap  of  the  potato-tuber  is  mixed  with  ammonia, 
no  precipitate  of  phosphate  of  magnesia  and  ammonia 
is  produced ;  but  this  precipitate  makes  its  appearance 
as  soon  as  the  fermentation  of  the  sap  has  destroyed 
the  (azotised)  substance  with  which  the  phosphate  of 
magnesia  is  combined. 

Careful  mixture  and  distribution  of  the  nutritive 
substances  present  in  the  soil,  are  the  most  important 
means  of  rendering  them  effective. 

A  piece  of  bone,  weighing  half  an  ounce,  placed  in 


DISTRIBUTION    RENDERS    FOOD   EFFECTIVE.  95 

a  cubic  foot  of  earth,  has  no  ^perceptible  influence  upon 
its  fertility  ;  but  when  uniformly  distributed  and  phys- 
ically combined  with  the  minutest  particles  of  the  same 
earth,  it  attains  a  maximum  of  efficacy.  The  influence 
of  the  mechanical  operations  of  agriculture  upon  the 
fertility  of  a  soil,  however  imperfectly  the  earthy  parti- 
cles may  be  mixed  by  the  process,  is  remarkable  and 
often  borders  upon  the  marvellous.  The  spade,  which 
breaks,  turns,  and  mixes  the  soil,  makes  a  field  much 
more  fruitful  than  the  plough,  which  breaks,  turns,  and 
displaces  the  earth,  without  mixing  it.  The  effect  of 
both  is  increased  by  the  harrow  and  the  roller,  so  that, 
in  the  very  same  places  where  a  crop  has  grown  during 
the  preceding  year,  a  fresh  crop  will  find  nutriment ;  in 
other  words,  the  earth  is  not  yet  exhausted. 

The  action  of  chemical  agents  in  distributing  the 
food-elements  of  plants  is  still  more  powerful  than  that 
of  the  mechanical.  By  applying,  in  proper  quantities, 
nitrate  of  soda,  salts  of  ammonia,  and  chloride  of  sodi- 
um, the  farmer  not  only  enriches  his  field  with  materials 
capable  of  taking  part  in  the  nutrition  of  plants,  but  he 
also  effects  a  distribution  of  the  ammonia  and  potash, 
thereby  replacing  or  aiding  the  mechanical  work  of  the 

E  lough,  and  the  influence  of  the  weather  in  the  time  of 
illow. 

We  are  in  the  habit  of  calling  c  manures  '  all  those 
materials  which,  when  applied  to  our  fields,  increase 
the  crops ;  but  the  same  effect  is  produced  by  the 
plough.  It  is  evident  that  the  mere  fact  of  a  favour- 
able influence  exerted  by  chloride  of  sodium,  nitrate  of 
soda,  salts  of  ammonia,  lime,  and  organic  matter, 
affords  no  conclusive  proof  that  these  have  acted  as 
nutritive  substances.  The  work  performed  by  the 
plough  may  be  compared  to  the  mastication  of  food  by 
those  special  organs  with  which  nature  has  endowed 
animals ;  and  nothing  can  be  more  certain  than  that 
the  mechanical  operations  of  agriculture  do  not  add  to 
the  store  of  nutritive  substances  in  a  field,  but  that 
they  act  beneficially  by  preparing  the  existing  nutri- 
ment for  the  support 'of  a  future  crop.  With  equal 


96  THE    SOIL. 

certainty  we  know  that  chloride  of  sodium,  nitrate  of 
soda,  salts  of  ammonia,  humus,  and  lime,  beside  the  ac- 
tion peculiar  to  their  elements,  perform  also  a  kind  of 
digestive  function  comparable  to  that  of  the  stomach  in 
animals,  and  in  which  they  may  partly  replace  each 
other.  These  substances,  therefore,  act  beneficially  upon 
those  kinds  of  soil  only  in  which  there  is  a  defect,  not 
in  the  quantity,  but  in  the  form  and  condition  of  the 
nutritive  elements  ;  and  they  may  accordingly  in  their 
permanent  action  be  replaced  by  a  mechanical  commi- 
nution, or  exceedingly  fine  pulverisation  of  the  soil. 

The  true  art  of  the  practical  farmer  consists  in 
rightly  discriminating  the  means  which  must  be  ap- 
plied to  make  the  nutritive  elements  in  his  field  effect- 
ive, and  in  distinguishing  these  means  from  others 
which  serve  to  keep  up  the  durable  fertility  of  the  land. 
He  must  take  the  greatest  care  that  the  physical  condi- 
tion of  his  ground  be  such  as  to  permit  the  smallest 
roots  to  reach  those  places  where  nutriment  is  found. 
'The  ground  must  not  be  so  cohesive  as  to  prevent  the 
spreading  of  the  roots. 

In  a  stiff,  heavy  soil,  plants  with  fine,  slender  roots 
will  never  thrive  well,  even  though  the  supply  of  nutri- 
tive ^substances  be  ample  ;  and  in  these  circumstances, 
the  beneficial  influence  of  green  manure  and  fresh  sta- 
ble dung  is  unmistakeable.  The  mechanical  condition 
of  the  soil  is,  in  fact,  altered  in  a  remarkable  wray  by 
the  ploughing  in  of  plants  and  their  remains.  A  stiff 
soil  loses  thereby  its  cohesion,  becoming  more  friable 
and  crumbling,  than  it  would  be  by  the  most  diligent- 
ploughing.  In  a  sandy  soil,  on  the  other  hand,  a  cer- 
tain cohesion  is  hereby  produced.  Every  stern  and 
leaf  of  the  green-manure  plants  ploughed  in,  opens  up, 
by  its  decay,  a  road  by  which  the  delicate  roots  of  the 
cereals  may  ramify  in  all  directions  to  seek  their  food. 
Here,  too,  we  must  always  remember,  that  the  effect 
calculated  to  be  produced  is  a  question  of  degree.  In 
many  fields,  the  roots  left  in  the  soil  of  a  fine  crop  of 
green  forage  plants  will  suffice  to  improve  a  succeeding 
cereal  crop  ;  and  a  field  from  which  a  crop  of  lupines 


FAVOURABLE   ACTION   OF   CLOVER   AND   TUENIPS.        97 

has  been  taken,  may  possibly  give  as  fine  a  succeeding 
cereal  crop  as  a  field  of  equal  extent  in  which  the  lu- 
pines have  been  ploughed  in. 

All  these  observations  tend  to  show  the  great  im- 
portance of  the  mechanical  conditions  which  impart  fer- 
tility to  a  soil  not  originally  deficient  in  the  means  of 
nourishing  plants  ;  and  that  a  comparatively  poorer  but 
well-tilled  soil,  if  its  physical  condition  is  more  favour- 
able for  the  activity  and  developement  of  the  roots, 
may  yield  a  better  harvest  than  richer  land.  In  like 
manner,  it  often  happens  that  the  cultivation  of  a  bulb- 
ous plant  renders  the  ground  better  suited  for  a  follow- 
ing cereal,  and  that  a  winter  crop  succeeding  a  green 
forage  plant,  turns  out  all  the  better,  the  richer  the 
previous  green  forage  crop  has  been,  or  rather  the  roots 
left  by  it. 

Clover  and  turnips  act  favourably  upon  a  succeed- 
ing winter  crop,  as  their  long  hardy  roots  move  the 
subsoil,  which  is  inaccessible  to  the  plough,  and  open 
it  for  the  roots  of  wheat.  Here  the  favourable  influ- 
ence upon  the  physical  condition  of  the  soil  far  out- 
weighs, for  the  wheat-plant,  the  injurious  effect  of  the 
decrease  in  the  quantity  of  the  chemical  conditions  re- 
sulting from  the  previous  turnip  and  clover  erops. 
Facts  of  this  nature  have  but  too  often  misled  practical 
agriculturists  to  surmise  that  the  physical  condition  is 
everything,  and  that  a  thorough  working  and  pulver- 
isation of  the  soil  will  suffice  to  command  a  good  crop. 
These  views,  however,  have  always  been  refuted  by 
time  ;  and  all  we  can  consider  established  is  this,  that 
for  a  series  of  years  the  restoration  of  a  proper  physical 
condition  in  the  soil  is  as  important  for  the  productive- 
ness of  many  fields  as  manuring,  and  often  more  so. 

The  influence  of  a  proper  physical  condition  of  the 
soil  upon  the  produce  can  hardly  be  more  convincingly 
proved  than  by  the  facts  which  agriculture  has  derived 
from  the  drainage  of  land,  under  which  we  comprise 
the  removal  of  the  subsoil  water  to  a  greater  depth,  and 
the  quicker  withdrawal  from  the  arable  soil  of  the  por- 
tion circulating  in  it.  A  great  many  fields  unsuited, 


98  THE    SOIL. 

by  their  constant  humidity,  for  the  cultivation  of  cereal 
plants  and  the  superior  kinds  of  forage  grasses,  have 
been  reclaimed  by  drainage,  and  made  lit  to  produce 
food  for  man  and  beast.  When  the  farmer,  by  means 
of  drainage,  keeps  within  bounds  the  amount  of  water 
in  his  fields,  he  controls  its  injurious  influence  at  all 
seasons ;  and  by  the  speedier  removal  of  the  water, 
which  soaks  the  earth  and  destroys  its  porosity,  a  path 
is  opened  for  the  air  to  reach  the  deeper  layers  of  the 
ground,  and  to  exercise  upon  these  the  sanre  beneficial 
influence  as  upon  the  surface  soil. 

In  winter,  the  earth  at  a  depth  of  3  to  4  feet  is 
warmer  than  the  external  atmosphere ;  hence  the  air 
coming  up  from  the  drain-pipes  may  contribute  to  keep 
the  temperature  of  the  arable  surface  higher  than  it 
would  be  without  this  current  of  air.  The  air  in  the 
drains  is  generally  richer  in  carbonic  acid  than  is  the 
case  with  atmospheric  air. 

The  effect  which  drainage  produces  upon  the  fer- 
tility of  land  may  in  itself  be  deemed  a  proof  thai, 
plants  cannot  derive  their  food  from  the  water  moving 
about  in  the  soil.  This  view  is  strongly  supported  by 
the  analysis  of  well,  drain,  and  spring  water.  (See  Ap- 
pendix D.) 

The  drainage-waters  contain  all  the  substances  which 
the  rain-water,  percolating  the  surface  soil,  is  capable 
of  dissolving  :  they  contain  various  salts  in  trifling  pro- 
portions, and  among  these  mere  traces  of  potash  ;  am- 
monia and  phosphoric  acid  are  generally  absent.  In 
analyses  specially  made  for  this  purpose,  Thomas  Way 
found  that  in  four  (drainage)  waters  no  appreciable 
quantity  of  potash  could  be  detected  in  10  pounds  of 
water ;  three  other  waters  were  found  to  contain  from 
2  to  5  pounds  of  potash  in  7,000,000  pounds  of  water. 
In  three  waters  no  appreciable  quantities  of  phosphoric 
acid  could  be  discovered :  four  other  waters  were 
found  to  contain  6  to  12  pounds  of  phosphoric  acid, 
and  0'6  to  1'8  pounds  of  ammonia  in  7,000,000  pounds 
of  water.  In  a  similar  series  of  analyses,  Krocker 
found  that  in  six  drainage-waters  no  appreciable  traces 


ANALYSIS    OF   DKAINAGE   WATEKS.  99 

of  phosphoric  acid  or  ammonia  could  be  detected ; 
while  four  other  drainage-waters  were  found  to  contain 
not  above  2  parts,  and  two  others  severally  4  and  6 
parts  of  potash,  in  1,000,000  parts  of  water. 

The  facts  now  stated  are  corroborated  by  a  series  of 
direct  and  most  instructive  experiments  made  by  Dr. 
Fraas,  to  ascertain  what  substances  the  rain  falling  in 
the  six  summer  months  takes  up  from  the  surface  soil 
and  carries  down  into  the  deeper  layers. 

In  lysimeters,  or  underground  rain-gauges  specially 
constructed  for  the  purpose,  a  collection  was  made  of 
the  rain-water,  which  trickled  through  a  layer  of  earth, 
6  inches  deep  by  1  square  foot  in  transverse  section, 
from  the  6th  April  to  the  Yth  October.  The  rain-gauge 
kept  at  a  neighbouring  observatory  indicated,  up  to  the 
1st  October,  a  fall  of  rain  amounting  to  480*7  millime- 
tres (18*75  inches).* 

Four  lysimeters  were  filled  with  the  same  earth 
taken  from  the  subsoil  of  the  stiff  clay  at  Bogenhausen  ; 
in  two  of  them  (III.  and  IY.)  the  earth  was  manured 
with  2  pounds  of  cow's  dung  ;  the  other  two  were  left 
unmanured.  Nos.  II.  and  IV.  were  sown  with  barley. 

Calculated  upon  a  square  metre  (10*75  square  feet) 
of  ground,  the  following  were  found  to  be  the  quanti- 
ties of  water  that  had  passed  through.  Dr.  Zoeller 
determined  the  amount  of  soluble  substances  contained 
in  the  water ;  the  quantities  of  phosphoric  acid  and 
ammonia  were  too  small  to  be  appreciable  : — 

*  The  lysimeter  consisted  of  a  square  box,  open  at  the  top,  closed  at 
the  bottom ;  at  a  depth  of  six  inches  from  the  open  top  a  sieve  was  in- 
serted, from  which,  up  to  the  rim,  the  box  was  filled  with  earth.  The 
rain  falling  upon  a  square  foot  of  surface,  and  trickling  through  the  six 
inches  of  earth,  was  collected  beneath  the  sieve,  in  the  box.  The  box  was 
buried  in  an  open  field,  up  to  the  border,  so  that  the  earth  in  it  was  level 
with  the  surface  of  the  field.  Two  lysimeters  were  filled  with  lime  soils 
from  the  banks  of  the  Isar ;  but  one  of  them  broke,  and  the  water  could 
not  be  collected :  hence  the  results  obtained  from  the  other  lost  their  im- 
portance as  a  comparative  experiment. 


100 


THE    SOIL. 


Lyeimeter. 

unman  u  red: 
and  without 
vegetation. 

II. 

unmanured: 
sown  with 
barley. 

III.         ;          IV. 

manured:     j     manured: 
without       j     sown  with 
vegetation.    \        barley. 

Quantity  of  perco- 
lated water  .... 

Quantity  of  potash 
contained  

Litres.     Pints. 
218=383-68 

Gramsi  Grains. 
0-516  =  8'0 

Kilog.  Ibs.  avr. 
5-16=11-35 

Litres.     Pints. 
213=374-88 

Grams.  Grains. 
0-434=6-7 

Kilog.  Ibs.  avr. 
4-34=9-5 

Litres.     Pints.  Litres.     Pints. 
304  =  535    i  144  =  253-5 

Grams.  Grains/Grams.  Grains. 
1-265  =  19-5|   0-552  =  8-5 

Kilog.  Ibs.  avr.  Kilog.  Ibs.  avr. 
12-65=27-81  5-52=12-1 

Or,  per  hectare,  of 
2-i  acres  .    . 

In  lysimeters  I.  and  II.  nearly  the  same  quantities 
of  water  percolated  through  the  earth ;  in  the  two 
others  the  difference  is  great ;  the  two  former  alone, 
therefore,  admit  of  comparison  as  regards  the  solvent 
power  of  the  water. 

These  experiments  show  that  less  than  one-half  of 
the  rain  falling  on  the  field  under  the  given  conditions, 
reached  a  depth  of  6  inches  ;  and  that,  calculating  for 
1  million  parts  of  water,  the  unmanured  soils  I.  and  II. 
gave  respectively  2*37  and  2'03  pounds,  the  manured 
soils  III.  and  IV.  5*46  and  3*82  pounds  of  potash.  The 
quantities  of  potash  in  the  manured  soils  do  not  exceed 
the  average  quantity  of  potash  found  in  drainage- 
water  (Krocker). 

The  barley  grown  in  the  earth  of  lysimeter  II.  pro- 
duced, per  square  metre,  137*3  grammes  (2120  grains) 
of  barley-corns,  and  147*9  grammes  (2272  grains)  of 
straw,  containing  in  their  ashes  (the  corns  in  2*47  per 
cent.,  the  straw  in  4*95  per  cent,  of  ash)  : — 


In  the  corns 
"     straw 

Total 


.     0*823  grammes  12-6  grains  of  potash 
.     1-410         "          21-8     "  " 


2-233 


34-4 


The  quantity  of  potash  absorbed  by  the  water  from 
the  earth  in  the  first  lysimeter,  which  was  not  sown 
with  barley,  amounted  altogether  to  0.516  gramme  (8*0 
grains) ;  in  the  second  lysimeter  to  0*434  gramme  (6*7 


MATTERS    DISSOLVED   BY   BAIN    WATER   IN    SOIL.       101 

grains).  The  difference  is  0'082  gramme  (1'3  grains). 
f  we  think  ourselves  warranted  in  concluding  "from 
this,  that  the  diminution  in  the  quantity  of  potash  in 
the  water  of  the  second  lysimeter  resulted  from  its  ab- 
sorption by  the  roots  of  the  barley,  we  should  be  neces- 
sarily led  to  infer  that  the  plants  received — 

By  the  agency  of  the  percolating  water      0*082  grammes       1*3  grs. 
Direct  from  the  soil      ....       2.151       "  33'2     " 

Total  .         .         .       2'233       "  34-5 

and,  accordingly,  96*4  per  cent,  direct  from  the  soil, 
and  3'6  per  cent,  from  the  water ;  that  is,  27  times 
more  from  the  former  than  from  the  latter. 

Let  us  now  assume,  from  the  results  obtained  with 
the  third  lysimeter,  which  was  filled  with  earth  richly 
manured  with  cow-dung,  that  the  rain-water  falling  on  a 
surface  of  one  hectare  (2-J-  acres)  of  land,  dissolves,  out 
of  a  layer  of  arable  surface  soil  6  inches  deep,  12-65 
kilogrammes  (27'8  Ibs.)  of  potash  ;  and  let  us  compare 
with  this  the  quantity  of  potash  withdrawn  from  a  hec- 
tare of  ground  by  a  potato  or  turnip  crop.  We  know 
that  an  average  potato  crop  from  a  hectare  contains  in 
the  tubers  204  kilogrammes  (449  Ibs.)  of  ash,  of  which 
100  kilogrammes  (220  Ibs.)  are  potash  ;  and  an  average 
turnip  crop,  572  kilogrammes  (1258  Ibs.)  of  ash,  of 
which  248  kilogrammes  (545  Ibs.)  are  potash  ;  and  we 
easily  perceive  that,  even  had  the  entire  amount  of  the 
potash  dissolved  by  the  rain  been  conveyed  into  the 
plants  to  serve  as  food,  yet  this  would  be  sufficient  to 
supply,  with  the  necessary  potash,  only  the  eighth  part 
of  the  potato  tubers  and  the  twentieth  part  of  the  tur- 
nips severally  produced  on  a  hectare  of  land.  The 
amount  of  potash  in  the  percolated  water  shows  the 
quantity  of  potash  which  the  water  could  possibly  ab- 
sorb ;  and  as  comparatively  but  a  small  portion  of  the 
percolating  water  comes  in  contact  with  the  roots  of 
the  plants,  and  can  give  up  potash  to  them,  it  is  clear 
that  the  constituents  of  the  solution  moving  about  in 
the  soil  have  but  a  very  trifling  share  in  the  process  of 
nutrition,  while  the  absence  from  it  of  ammonia  and 


102  THE    SOIL. 

phosphoric  acid  is  of  itself  sufficient  to  prove  that  these 
materials  in  the  soil  cannot  change  their  place.  The 
ground  must  contain  a  certain  amount  of  moisture  to 
be  able  to  furnish  food  to  plants  ;  but  it  is^not  necessary 
for  their  growth  that  the  water  should  be  free  to  move 
about.  It  is  well  known  that  stagnant  water  in  the 
soil  is  injurious  to  most  of  the  cultivated  plants ;  and 
the  favourable  effect  upon  their  growth  produced  by 
draining  just  depends  on  this,  that  an  out  let -is  opened 
to  the  water  moving  by  the  force  of  its  own  gravity, 
and  the  earth  is  moistened  by  that  water  only  which  is 
retained  by  capillary  attraction. 

If  we  regard  the  porous  earth  as  a  system  of  capil- 
lary tubes,  the  condition  which  must  render  them  best 
suited  for  the  growth  of  plants  is  unquestionably  this, 
that  the  narrow  capillary  spaces  should  be  filled  with 
water,  the  wide  spaces  with  air,  and  that  all  of  them 
should  be  accessible  to  the  atmosphere.  In  a  moist 
soil  of  the  kind,  affording  free  access  to  atmospheric 
air,  the  absorbent  root-fibres  are  in  most  intimate  con- 
tact with  the  earthy  particles  ;  the  outer  surface  of  the 
root-fibres  may  here  be  supposed  to  form  the  one,  the 
porous  earthy  particles  the  other  wall  of  a  capillary 
vessel,  the  connection  between  them  being  effected  by 
an  exceedingly  thin  layer  of  water.  This  condition  is 
equally  favourable  for  the  absorption  of  fixed  and  of 
gaseous  elements  of  food.  If,  on  a  dry  day,  a  wheat  or 
barley-plant  is  cautiously  pulled  up  from  a  loose  soil,  a 
cylinder  of  earthy  particles  is  seen  to  adhere  like  a 
sheath  round  every  root-fibre.  It  is  from  these  earthy 
particles  that  the  plant  derives  the  phosphoric  acid,  pot- 
ash, silicic  acid,  &c.,  as  well  as  the  ammonia.  These 
substances  are  introduced  into  the  plant  by  means  of 
the  thin  layer  of  water,  the  molecules  of  which  are  in 
motion  only  in  so  far  as  the  roots  exercise  an  attractive 
power  upon  them. 

From  the  composition  of  spring-water,  and  the 
water  of  brooks  and  rivers,  every  single  drop  of  which 
has  been  in  contact  with  rocks,  or  with  the  soil  of  for- 
ests and  fields,  we  see  what  exceedingly  minute  quanti- 


WHY    SALTS   ARE   FOUND    IN    STAGNANT   POOLS.        103 

ties  of  phosphoric  acid,  ammonia,  and  potash  are  taken 
up  by  water  from  the  earth.  In  the  analysis  of  water 
taken  from  six  different  springs,  Graham,  Miller,  and 
Hofmann  found  no  appreciable  traces  of  ammonia  and 
phosphoric  acid.  In  the  water  of  Whitley,  there  was, 
in  37,000  gallons  (370,000  pounds  English),  1  pound  of 
potash,  or  1  kilogramme  in  135  cubic  metres :  just  the 
same  in  38,000  gallons  from  the  Critchmere  spring ;  in 
32,000  gallons  from  Yelwool ;  in  145,000  gallons  from 
Hindhead ;  in  55,000  gallons  from  the  Hasford  Mill- 
brook  ;  and  in  17,700  gallons  from  the  spring  near  Cos- 
ford  House.  The  water  of  the  Brunthal  spring,  near 
Munich,  which  is  used  for  drinking  in  a  large  portion 
of  the  city,  contains  no  ammonia,  no  phosphoric  acid, 
and  in  87,000  pounds,  1  pound  of  potash. 

From  these  and  other  analyses  of  spring,  well,  and 
drainage  water,  we  are  not  warranted  in  concluding 
that  potash,  ammonia,  and  phosphoric  acid  are  deficient 
in  the  water  of  all  springs,  brooks,  and  rivers ;  on  the 
contrary,  it  is  quite  certain  that  the  water  in  many 
marshes  contains  both  potash  and  phosphoric  acid  in 
notable  quantities.* 

The  presence  of  potash,  phosphoric  acid,  iron,  and 
sulphuric  acid,  in  the  water  of  stagnant  pools,  is  easily 
explained. 

*  Thus  a  litre  (1'76  pints)  of  water  taken  from  an  artificial  pond  in  the 
Botanic  Garden  at  Munich,  left  a  residue  of  0'425  gramme  (6'5  grains), 
which  contained,  in  100  parts — 

Lime   .  35'000 


Magnesia 

Chloride  of  sodium 
Potash 
Soda 


.       12-264 
10-100 
3-970 
0-471 
0-721 
2-619 
8-271 
Silicic  acid 3*240 

Incombustible  constituents   .        .        .  76-656 

Water  lost  .        .        .        .        .        .        .       23-344 


Sesquioxide  of  iron  with  alumina 
Phosphoric  acid. 
Sulphuric  acid 


100-000 


104  THE    SOIL. 

In  a  stagnant  pool  or  bog  are  gradually  collected 
the  remains  of  dead  generations  of  plants,  the  roots  of 
which  have  drawn  a  quantity  of  mineral  matter  from  a 
certain  depth  of  the  soil.  These  vegetable  remains  un- 
dergo decomposition  at  the  bottom  of  the  pools,  and 
their  inorganic  elements,  or  ash-constituents,  are  dis- 
solved by  the  aid  of  carbonic  acid,  and  perhaps  also  of 
organic  acids.  They  remain  dissolved  in  the  water, 
when  the  surrounding  mud  and  the  earth  in  contact 
with  this  solution  have  been  completely  saturated  with 
them. 

Scherer  found  in  the  three  wells  at  Briickenau  all 
the  substances  contained  in  the  water  above-mentioned, 
of  the  Botanic  Garden  pond,  besides  acetic,  formic, 
butyric  and  propionic  acids.  The  mountains  all  around 
Briickenau  are  formed  of  variegated  sandstone  (Bimter 
sandstein} ;  the  vegetation  of  the  whole  surrounding 
country  is  most  luxuriant,  resembling  the  primeval  for- 
ests ;  there  are  numerous  oak-lands  and  beech-lands, 
with  trees  nearly  a  thousand  years  old.  Hence  Scherer 
is  led  to  attribute  the  composition  of  the  well-water  at 
Briickenau  to  the  solvent  action  of  rain  percolating 
through  a  humose  soil  rich  in  decaying  vegetable  sub- 
stances. ('  Annal.  der  Chem.  und  Pharm.'  i.  c.  285.) 

It  is  clear  that  wherever  conditions  have  been  at 
work  similar  to  those  under  which  the  bog-water  in  the 
Botanic  Garden  of  Munich  and  the  wells  of  Briickenau 
have  been  formed,  the  water  found  on  the  surface  of 
the  earth,  in  pools,  springs,  or  brooks,  will  contain  in 
the  most  varying  proportions  nutritive  elements  useful 
to  plants,  such  as  phosphoric  acid  and  potash,  which 
are  not  found  in  other  waters.  In  like  manner,  an 
arable  soil  rich  in  vegetable  remains,  in  which,  from 
the  processes  of  decay  incessantly  going  on,  products 
of  an  acid  character  are  generated,  will  be  able  to  give 
up,  to  the  rain-water  percolating  through  it,  phosphoric 
acid  and  alkalies,  which  are  thus  carried  down  to  the 
deeper  layers,  and  appear  in  the  drainage  water.  The 
quantity  of  these  substances  dissolved  in  the  water  will 
depend  upon  the  condition  of  the  soil  on  which  the 


FERTILISING   EFFECT   OF   BOG   SOIL   AND   MUD.          105 

plants  grow,  the  ash-constituents  of  which  are  carried 
away  by  the  rain-water,  from  their  decaying  remains. 
Where  the  ground  is  rocky,  covered  with  a  thin  coat- 
ing of  earth  and  a  thick  clothing  of  foliage,  the  water 
which  runs  off  will  carry  down  to  the  lower  layers  all 
the  more  fixed  elements  of  vegetable  food,  in  propor- 
tion as  the  layer  of  earth  itself  retains  less  of  them. 
The  finer  earthy  particles  of  such  a  soil,  washed  away 
by  heavy  rains,  are  carried  down  by  torrents  to  the 
valleys  and  low  lands,  and  form  a  soil  of  all  degrees  of 
fertility  according  to  their  chemical  condition,  which 
determines  their  power  of  absorbing  dissolved  nutritive 
substances.  But  these  layers  of  earth  formed  from  the 
mud  borne  down  by  the  torrents  will  always  either  be 
saturated,  or  gradually  become  saturated  with  the  nu- 
tritive substances  contained  in  the  water,  from  which 
they  are  deposited.  This,  perhaps,  explains  the  differ- 
ence in  the  fertilising  effects  of  the  waters  used  for  irri- 
gating meadows,  which  must  necessarily  vary  very 
much  according  to  the  source  of  the  water  ;  that  which 
has  collected  on  hills  covered  with  a  rich  vegetation,  or 
has  been  derived  from  overflowing  stagnant  pools,  will 
doubtless  convey  manuring  matters  to  the  meadow- 
lands  ;  whilst  water  flowing  from  bare  mountains  can- 
not, in  this  particular  respect,  exert  any  action  upon 
the  increase  of  the  grass  crop.  If  such  increase  takes 
place  notwithstanding,  the  cause  must  be  sought  else- 
where. 

In  many  places  bog-soil,  and  the  mud  from  ditches, 
stagnant  waters  and  ponds,  are  highly  esteemed  as  fer- 
tilising agents  ;  and  their  influence  is  explained  by  the 
fact,  that  their  smallest  particles  are  saturated  with 
manuring  matters,  or  elements  of  the  food  of  plants. 
The  same  remark  applies  to  the  fertility  of  many  tracts 
of  cleared  wood-land,  wThere  the  soil  for  forty  or  eighty 
years,  or  even  longer,  has  received  from  the  layer  of 
foliage  and  vegetable  remains  decaying  on  it,  a  certain 
supply  of  ash  constituents,  drawn  from  a  great  depth, 
which  are  retained  by  the  upper  layers  of  the  porous 
soil,  and  serve  to  enrich  it. 

5* 


106  THE    SOIL. 

The  injury  done  to  wood-lands  by  raking  away  the 
leaves  cannot  be  explained  merely  upon  the  assumption 
that  the  soil  is  deprived  of  its  ash-constituents,  which 
are  taken  away  with  the  foliage ;  for,  in  themselves, 
the  fallen  leaves  and  twigs  are  poor  in  nutritive  sub- 
stances, especially  potash  and  phosphoric  acid ;  and 
besides,  these  elements  do  not  reach  the  deeper  layers 
of  the  soil,  where  they  might  be  again  absorbed  by  the 
roots.  The  injury  is,  perhaps,  rather  attributable  to 
the  fact,  that  the  remains  of  leaves  and  plants  consti- 
tute a  lasting  source  of  carbonic  acid,  which,  carried  by 
rain  to  the  deeper  layers,  must  powerfully  contribute 
to  disintegrate  and  decompose  the  earthy  particles.  In 
a  dense  wood,  where  the  air  is  more  rarely  renewed 
than  in  the  open  plain,  this  supply'  of  carbonic  acid  is 
important ;  moreover,  the  thick  carpet  of  leaves  pro- 
tects the  ground  from  being  dried  by  the  air,  and  main- 
tains it  in  a  permanent  state  of  moisture,  particularly 
useful  to  foliaceous  trees,  which  exhale  from  their 
leaves  larger  'quantities  of  water  than  the  coniferous 
plants. 

To  understand  the  operations  of  agriculture,  it  is 
indispensably  necessary  that  the  farmer  should  have 
the  clearest  knowledge  of  the  manner  in  which  plants 
derive  their  nutriment  from  the  soil. 

The  opinion  that  the  roots  of  plants  extract  their 
food  immediately  from  those  portions  of  the  soil  which 
are  in  direct  contact  with  their  absorbent  surfaces,  does 
not  imply  that  potash,  lime,  or  phosphate  of  lime,  in 
the  solid,  undissolved  state  can  penetrate  the  membrane 
of  the  cells  ;*  nor  does  it  imply  that  the  nutritive  sub- 

*  If  a  glass  vessel  is  filled  to  the  brim  with  water,  in  which  are  a  few 
drops  of  hydrochloric  acid,  and  covered  closely  with  a  piece  of  bladder,  so 
that  the  water  moistens  the  bladder  and  no  air  is  left  between  them,  and 
the  outside  of  the  bladder  is  carefully  dried,  it  may  then  be  seen  how  a 
solid  body,  without  the  cooperation  of  a  fluid  from  the  outside,  can  make 
its  way  through  the  bladder  to  the  water  in  the  glass.  For  if  a  little  chalk 
or  finely-pulverised  phosphate  of  lime  is  strewed  upon  the  dried  outer  sur- 
face of  the  bladder,  the  powder  will  disappear  in  the  course  of  a  few  hours, 
and  the  usual  reactions  will  show  the  presence  of  lime  and  phosphate  of 
lime  in  the  fluid. 

Of  course  the  passage  of  the  carbonate  and  phosphate  of  lime  in  the 


MANNER   IN    WHICH   KOOTS    TAKE    UP    FOOD.  107 

stances  held  in  solution  by  the  water  moving  about  in 
the  soil  may  not,  under  certain  circumstances,  be  ab- 
sorbed by  the  roots  of  the  plants.  But  it  is  based  upon 
the  assumed  fact,  that  the  roots  receive  their  food  from 
the  thin  layer  of  water  which,  retained  by  capillary 
attraction,  is  in  intimate  contact  with  the  earth  and 
with  the  root  surface,  and  not  from  more  remote  layers' 
of  water ;  that  between  the  root  surface,  the  layer  of 
water,  and  the  earthy  particles,  a  reciprocal  action  goes 
on,  which  does  not  take  place  between  the  water  and 
the  earthy  particles  alone.  It  also  assumes  as  proba- 
ble, that  the  nutritive  substances  adhering,  in  a  state 
of  exceedingly  minute  division,  to  the  outer  surface  of 
the  earthy  particles,  are  in  direct  contact  with  the  fluid 
of  the  porous  absorbent  cell-walls,  by  means  of  a  very 
thin  layer  of  water  ;  and  that  the  solution  of  the  solid 
elements  is  effected  in  the  pores  of  the  cell-walls, 
whence  they  pass  immediately  into  the  system  of  the 
plant. 

The  facts  in  support  of  this  view,  briefly  recapitu- 
lated, are  as  follow :  The  roots  of  all  land-plants,  and 
of  most  marsh-plants,  are  in  direct  contact  with  the 
earthy  particles.  These  particles  of  earth  have  the 
power  of  attracting  the  most  important  elements  of 
food  conveyed  to  them  in  watery  solution  (such  as  pot- 
ash, phosphoric  acid,  silicic  acid,  ammonia),  and  of  re- 
taining them,  just  as  charcoal  retains  colouring  matters. 
In  most  cases  that  have  been  investigated  it  has  been 
found  that  the  water  moving  about  in  the  ground  ex- 
tracts from  the  soil  scarcely  any  appreciable  quantities 
of  ammonia,  no  phosphoric  acid,  and  potash  in  such 
trifling  quantities,  that  all  these  together  are  quite  in- 
sufficient to  afford  the  requisite  supply  of  these  ele- 
ments to  the  plants  growing  in  the  field. 

solid  state  through  the  bladder  into  the  water,  is  only  apparent.  Both 
salts  are  dissolved  in  the  pores  of  the  membrane  where  they  come  in  con- 
tact with  the  acidulated  water,  and  as  the  evaporation  of  the  water  from 
the  bladder  somewhat  diminishes  the  inner  pressure  as  compared  to  the 
outer,  the  stronger  outer  pressure,  assisted  by  the  solvent  power  of  the 
water,  forces  the  solution  inward. 


108 


THE    SOIL. 


"Water  stagnant  in  the  ground,  so  far  from  promot- 
ing the  absorption  of  food,  injures  the  growth  of  land- 
plants. 

If  plants  really  did  receive  the  elements  of  their 
food  from  a  solution  which  could  change  its  place  in 
the  soil,  then  all  drainage  waters,  spring,  brook,  and 
river  waters,  must  contain  the  principal  nutritive  sub- 
stances of  all  plants  ;  and  it  must  be  'quite  practicable, 
by  continued  lixiviation,  to  extract  from  every  arable 
soil,  without  distinction,  all  the  nutritive  substances, 
either  entirely,  or  at  least  in  amount  corresponding  to 
the  quantity  contained  in  a  crop.  But,  in  reality,  this 
is  not  practicable.  By  the  action  of  water,  the  field 
loses  none  of  the  principal  conditions  of  its  fertility,  in 
such  a  degree  as  perceptibly  to  impair  the  growth  of 
plants  cultivated  on  it. 

For  thousands  of  years,  all  fields  have  been  exposed 
to  the  lixiviating  action  of  rain-water,  without  losing 
their  powers  of  fertility.  In  all  parts  of  the  earth, 
where  man  for  the  first  time  draws  furrows  with  the 
plough,  he  finds  the  arable  crust,  or  top  layer  of  the 
field,  richer  and  more  fertile  than  the  subsoil.  The  fer- 
tility of  the  ground  is  not  diminished  by  plants  grow- 
ing thereon  ;  not  until  the  plants  are  removed  from  the 
ground  does  it  gradually  lose  its  fruitfulness. 

The  opinion  that  some  cause  is  at  work  within  the 
plant  itself,  which  seems  to  render  soluble  certain  ele- 
ments of  food,  and  make  them  available  for  nutrition,  is 
not  contradicted  by  the  experiments  of  Knop,  Sachs, 
and  STOHMANN,  who  have  shown  that  many  land-plants, 
without  touching  a  particle  of  earth,  may  be  brought 
to  flowering  and  seed-bearing  in  water,  to  which  the 
mineral  elements  of  food  have  been  added.  These  ex- 
periments, which  have  thrown  considerable  light  upon 
the  physiological  importance  of  the  several  nutritive 
substances  (see  Appendix  E.),  merely  prove  how  ad- 
mirably the  ground  is  adapted  to  the  requirements  of 
plants,  and  how  much  human  ingenuity,  knowledge, 
and  minute  care,  it  takes  to  supply,  under  circum- 
stances differing  so  widely  from  the  natural  condition, 


PLANTS    GROWN    IN    SOIL   AND    IN   WATER.  109 

certain  properties  of  arable  soil,  whicli  insure  the 
healthy  growth  of  plants. 

If  the  supply  of  nutritive  substances  in  a  state  of 
solution  were  really  suited  to  the  nature  of  the  plant 
and  the  functions  of  the  roots,  it  would  follow  that  in 
such  a  solution,  most  abundantly  provided  with  all  the 
elements  of  food  in  the  most  movable  form,  the  plants 
must  thrive  the  more  luxuriantly  the  fewer  the  obsta- 
cles are  which  oppose  their  absorption  of  food. 

A  young  rye-plant,  placed  in  a  fertile  soil,  will 
often  send  forth  a  bunch  of  thirty  or  forty  stalks,  each 
of  them  bearing  an  ear,  and  will  yield  a  thousandfold 
crop  of  grains,  or  even  more ;  yet  this  plant  draws  its 
mineral  food  from  a  volume  of  earth,  from  which  the 
most  persevering  lixiviation  with  pure  water,  or  water 
containing  carbonic  acid,  will  not  extract  even  the  one- 
hundredth  part  of  the  phosphoric  acid  and  nitrogen, 
nor  the  fiftieth  part  of  the  potash  and  the  silicic  acid, 
which  the  plant  has  drawn  from  the  soil.  How  is  it 
then  possible,  under  such  circumstances,  to  assume  that 
water  alone  would  have  sufficed,  by  virtue  of  its  solvent 
power,  to  render  available  to  the  plant  all  the  sub- 
stances found  in  it  \ 

None  of  the  plants  grown  in  watery  solutions  of  the 
mineral  elements  of  their  food,  even  though  thriving 
luxuriantly,  will  bear  the  remotest  comparison,  in  the 
bulk  of  vegetable  matter  produced,  with  plants  grown 
in  a  fertile  soil ;  and  the  entire  process  of  developement 
in  them  proves  that  the  conditions  of  thriving  growth 
in  the  soil  are  quite  of  another  kind. 

The  greatest  weight  of  crop  obtained  by  Stohmann 
from  an  Indian  corn  plant  grown  in  water  amounted  to 
84  grammes ;  while  he  obtained  from  another  Indian 
corn  plant  grown  in  the  soil,  at  the  same  time  and  from 
the  same  seed,  a  crop  weighing  346  grammes.  In  Knop's 
experiments,  the  dry  weight  of  two  Indian  corn  plants, 
the  one  grown  in  water,  the  other  in  the  soil,  was  found 
to  be  as  1 :  Y. 

The  water  circulating  in  the  soil  contains  chloride 
of  sodium,  lime,  and  magnesia — the  two  latter  in  com- 


110  THE    SOIL. 

bination  partly  with  carbonic  acid,  partly  with  mineral 
acids ;  and  there  can  hardly  be  a  doubt  but  that  the 
plant  absorbs  a  portion  of  these  substances  from  the 
solution.  The  same  must  apply  equally  to  potash, 
ammonia,  and  the  dissolved  phosphates  ;  but  the  water 
circulating  in  the  soil,  in  a  normal  condition,  either  does 
not  hold  the  three  last-named  substances  in  solution,  or 
not  in  sufficient  quantities  to  supply  the  demands  of 
the  plant. 

According  to  the  ordinary  rules  of  natural  science, 
when  we  seek  to  explain  a  phenomenon,  we  leave  out 
of  view  those  cases  in  which  the  conditions  superinduc- 
ing the  phenomenon  are  clear  and  patent.  For  in- 
stance, if  we  find  in  bog-water  all  the  ash-constituents 
of  duckweed,  there  can  be  no  doubt  about  the  form  in 
which  they  passed  into  the  plant ;  they  were  dissolved 
in  water,  and  they  were  absorbed  in  a  soluble  state. 
In  such  a  case,  we  have  merely  to  explain  the  reason 
why  the  several  ash-constituents,  being  all  present  in 
one  and  the  same  form,  have  yet  passed  into  the  plant 
in  unequal  proportions. 

If,  in  another  case,  WTC  find  that  the  rain-water 
which  falls  on  a  given  area  of  land,  dissolves  out  of  the 
soil  many  times  more  potash  than  was  contained  in  a 
crop  of  turnips  grown  on  that  area,  there  is  every  rea- 
son to  assume  that  the  turnip,  like  the  duckweed,  has 
absorbed  the  needful  potash  from  a  solution.  But,  if 
in  the  entire  quantity  of  water  which  falls  on  the  field 
during  the  period  of  vegetation,  we  find  only  just  so 
much  potash  as  the  turnip  crop  requires,  and  no  more, 
the  assumption  that  the  potash  in  the  turnips  has  been 
derived  from  this  solution  would  necessarily  involve 
the  impossible  supposition,  that  all  the  watery  particles 
containing  potash  must  have  been  in  contact  with  the 
roots  of  the  turnips ;  otherwise,  the  latter  could  not 
have  absorbed  so  much  potash  as  is  actually  found  in 
them.  This  supposition  is  impossible  ;  because,  during 
the  time  when  the  turnip  vegetates,  there  is  generally 
no  water  circulating  in  the  soil — such,  for  instance,  as 
might  be  carried  oft  by  drain-pipes. 


IN    WHAT   MANNEK   PLANTS    ABSOEB   FOOD.  Ill 

If  the  examination  of  the  water  in  the  soil  shows  it 
to  contain  half  the  quantity  of  potash  required  by  a 
turnip  crop,  there  is  no  need  to  explain  how  the  dis- 
solved half  of  the  potash  has  passed  into  the  turnip- 
plant,  but  in  what  form  and  manner  the  plant  has  ab- 
sorbed the  other  half  deficient  in  the  -water. 

If,  again,  by  the  examination  of  the  water  in  other 
fields,  we  find 'that  it  contains  only  J ;  nay,  only  -J-,  ^ 
or  -^  of  the  quantity  of  potash  found  in  a  turnip  crop 
grown  upon  it ;  and  if  we  further  ascertain  that  in  a 
soil,  favourable  for  the  growth  of  turnips,  the  plant 
always  takes  up  the  same  quantity  of  potash  from  the 
ground,  no  matter  how  much  or  how  little  of  that  sub- 
stance the  water  circulating  in  the  soil  dissolves  from 
the  earth  ;  it  follows,  that  as  the  water,  the  soil,  and  the 
plant,  can  alone  come  into  consideration  here,  the  direct 
power  of  the  water  to  dissolve  potash  is  of  no  impor- 
tance to  the  plant ;  and  that  the  plant  itself,  by  the 
help  of  water,  must  have  rendered  the  needful  potash 
soluble. 

What  is  here  asserted  of  one  constituent,  holds  good 
for  all.  If,  therefore,  we  find,  that  by  treating  a  soil 
with  rain-water  we  can  dissolve  from  it  potash,  phos- 
phoric acid,  and  ammonia  or  nitric  acid,  in  sufficient 
quantity  to  account  for  the  presence  of  these  substances 
in  the  cereal  plants  grown  on  such  a  soil ;  while,  on  the 
other  hand,  we  find  that  the  plant  contains  a.  hundred 
times  more  silicic  acid  than  the  water  could  possibly 
have  supplied ;  the  cause  of  the  absorption  of  silicic 
acid,  which  clearly  is  not  in  the  water,  must  again  here 
be  sought  for  in  the  plant  itself.  Again,  if  other  cases 
show  that  an  equally  abundant  crop  of  corn  is  obtained 
on  fields,  from  which  water  fails  to  extract  phosphoric 
acid  or  ammonia,  here,  too,  we  are  led  to  the  conclusion 
that  the  nutritive  substances  dissolved  in  the  water  are 
of  no  special  importance  to  the  plants  in  question  ;  but 
that,  as  an  indispensable  requisite,  these  elements  must 
possess  the  form  most  suitable  for  the  action  of  the  root, 
be  this  what  it  may. 

The  beautiful  experiments  on  vegetation  made  con- 


112  THE    SOIL. 

jointly  by  Professor  Nageli  and  Dr.  Zoeller,  in  the 
Botanic  Garden  at  Munich,  most  strikingly  prove  the 
correctness  of  the  conclusions  to  which  the  analysis  of 
drainage  and  other  waters  has  led.  Instead  of  growing 
plants  in  solutions  of  the  mineral  elements  of  their  food, 
as  had  been  done  in  all  previous  experiments,  they  pur- 
sued the  very  opposite  course ;  they  placed  the  -seeds 
of  the  plants  in  a  soil  containing  all  the  elements  of 
their  food  in  an  insoluble  state. 

In  such  experiments,  it  is  not  easy  to  find  a  material 
which  can  be  used  as  a  substitute  for  arable  soil,  and 
possessing  all  its  properties ;  and  the  difficulty  is  proved 
by  the  fact,  that  none  of  the  plants  grown  by  Boussin- 
gault  and  others,  in  an  artificial  soil,  abundantly  pro- 
vided with  all  the  elements  of  food,  could  even  remotely 
bear  comparison  with  a  plant  grown  in  a  fertile  arable 
soil.  Pulverised  charcoal  or  pumice-stone  have  the 
power  of  extracting  many  elements  of  the  food  of  plants 
from  their  solutions,  and  physically  fixing  them ;  but 
they  have  not,  in  the  moist  state,  that  soft,  plastic,  and 
yielding  condition  of  the  -clay  in  arable  soil,  which  per- 
mits the  intimate  contact  of  the  roots  with  the  earthy 
particles.  The  best  substitute  for  the  purpose  is  coarse- 
ly-powdered turf,  which,  in  the  moist  state,  forms  a 
plastic  mass,  bearing  a  remote  resemblance  to  clay,  and, 
like  arable  soil,  absorbs  all  elements  of  the  food  of 
plants  from  their  solutions.  Accordingly  Nageli  and 
Zoeller  used  in  their  experiments  coarsely-powdered 
turf  as  the  vehicle  of  the  nutritive  substances,  after  hav- 
ing ascertained  its  absorptive  power  for  the  several  ele- 
ments of  food. 

A  litre  (1*76  pint)  of  turf,  weighing  324  grammes 
(4 987 '6  grs.),  was  found  to  absorb  from  solutions  of  car- 
bonate of  potash,  carbonate  of  ammonia,  carbonate  of 
soda,  and  phosphate  of  lime — 1*45  grammes  (22*4  grs.) 
of  potash,  1*227  grammes  (19  grs.)  of  ammonia,  0*205 
gramme  (3*2  grs.)  of  soda,  and  0*890  gramme  (13*7  grs.) 
of  phosphate  of  lime  equal  to  0*410  gramme  (6*3  grs.) 
of  phosphoric  acid. 

The  quantities  of  potash  and  ammonia  here  given  do 


ABSORPTIVE   POWER   OF   TUKF.  113 

not  show  the  total  amounts  of  these  substances  which 
the  turf  will  absorb  to  the  point  of  complete  saturation, 
but  merely  what  it  will  take  lip  when  simply  mixed 
with  the  solutions,  and  left  in  contact  with  them  for  a 
few  hours.  If  we  add  more  of  these  solutions  to  the 
turf-powder,  the  fluid  exhibits  an  alkaline  reaction, 
which  disappears  again  after  one  or  more  days  ;  and  it 
is  only  at  the  end  of  eight  days,  when  the  litre  (1'76 
pint)  of  turf  has  taken  up  7*892  grammes  (121*6  grs.)  of 
potash  and  4*169  grammes  (64*2  grs.)  of  ammonia,  that 
the  alkaline  reaction '  remains  permanent.  What  we 
shall  hereafter  designate  as  saturated  turf  contains 
only  i  of  the  potash  and  -J-  of  the  ammonia,  which 
would  be  absorbed  by  that  substance  to  the  point  of 
complete  saturation. 

To  represent  different  soils,  containing  various  pro- 
portions of  nutritive  substances,  three  mixtures  were 
made  of  saturated  and  ordinary  turf-powder  : — 

1  mixture  contained  1  vol.  of  saturated  tnrf-powder, 

and  1  vol.  of  dry  turf-powder, 
3  "  1  'k    3  4fc  u 

These  mixtures  represented  different  kinds  of  earth,  in 
each  volume  of  which  the  third  contained  one-fourth, 
the  second  one-half  the  quantity  of  the  nutritive  sub- 
stances present  in  the  first. 

The  pure  turf  contained  2'5  per  cent,  of  nitrogen, 
and  100  grammes  yielded  4'4  grammes  of  ash,  which, 
upon  analysis,  were  found  to  contain  0*115  gramme  of 
potash,  0-0576  gramme  of  phosphoric  acid,  besides  lime, 
sesquioxide  of  iron,  silicic  acid,  magnesia,  sulphuric 
acid,  and  soda.  (See  more  fully  in  Appendix  E.) 

With  each  of  these  mixtures  a  pot  was  filled,  each 
pot  holding  8%  litres  (2592  grammes,  —  39917  grs.)  ;  a 
fourth  pot,  of  similar  size,  contained  dry  turf-powder. 

Taking  into  consideration  the  amount  of  ash  in 
ordinary  turf,  the  four  pots  severally  contained  the  fol- 
lowing quantities  of  nutritive  substances  : — 


THE    SOIL. 


1st  Pot, 
with  common 
turf. 

2d  Pot, 
quarter  saturated 
turf. 

3d  Pot, 
half  saturated 
turf. 

4th  Pot, 
fully  saturated 
turf. 

Nitrogen.  .  . 
Potash  .... 
Phosphoric  ) 
acid  .  .  .  ) 

Grams.       Grains. 
71'        =1093-5 
3-18   =     49-0 

1-586=     24-4 

Grams.   Grains. 
2-60   =40-0 
3-075=47-4 

0-83  =12-8 

Grams.  Grains. 
4-32=66-5 
6-15=94-7 

1-75=27-0 

Grams.  Grains. 
8-65  =  133-2 
12-30=189-5 

3-49=   53-8 

The  figures  showing  the  quantities  of  nitrogen,  pot- 
ash, and  phosphoric  acid,  express  the  amount  of  nitro- 
gen in  the  dry  turf  (in  the  first  pot),  and  the  amount  of 
potash  and  phosphoric  acid  in  its  ash.  For  the  other 
pots,  the  figures  express  the  quantity  of  nutritive  sub- 
stances which  had  been  added. 

In  each  of  these  pots,  five  dwarf-beans  were  planted, 
the  weight  of  which  had  been  carefully  determined,  and 
which  had  been  allowed  to  germinate  in  pure  water. 

The  plants  in  the  three  manured  pots  grew  very 
evenly,  and  the  luxuriance  of  their  growth  excited  the 
astonishment  of  all  who  saw  them. 

During  the  first  month,  the  plants  in  pots  2  and  3 
(filled  respectively  with  turf  J  and  %  saturated)  pre- 
sented a  finer  appearance  than  the  others  ;  but  those  in 
pot  4  (filled  with  saturated  turf)  soon  overtook  them ; 
and  the  difference  in  the  size  of  the  leaves,  in  propor- 
tion to  the  greater  richness  of  the  soil,  was  very 
striking. 

Remarkable,  too,  was  the  influence  of  the  soil  upon 
the  term  of  the  vegetating  period.  Each  of  the  five 
plants  in  the  pure  turf  produced  a  small  pod,  and,  to- 
gether, the  five  pods  contained  14  seeds.  During  the 
ripening  of  the  seeds,  the  leaves  died  from  below  up- 
wards ;  so  that,  before  the  pods  had  turned  yellow,  all 
the  leaves  had  fallen  off.  The  plants  in  the  saturated 
turf  remained  green  longer  than  any  of  the  others,  and 
their  seeds  ripened  latest.  The  last  pod  of  these  plants 
was  cropped  on  July  29,  whilst  the  last  pod  of  the 
plants  in  the  pure  turf  had  already  been  cropped  on 
July  16. 


GROWTH   OF   BEANS    IN   EXPERIMENTAL    SOIL.          115 


The  following  table  shows  the  crops  yielded  by  all 
four  pots,  with  the  number  and  weight  of  the  seeds  : — 


1st  Pot, 
pure  turf. 

2<1  Pot, 
turf  quarter 
saturated. 

3d  Pot, 
turf  half 
saturated. 

4th  Pot, 
turf  fully 
saturated. 

Number  gathered.  .  .  . 
"         sown 

Beans. 

14 
5 

Beans. 

79 
5 

Beans. 
80 
5 

Beans. 
103 
5 

Gathered  
Sown         .       ... 

Grammes. 

7'9 
3-965 

Weight  in 
Grammes. 
56:7 
3'88 

Grammes. 
Grammes. 
74-3 

4-087 

Grammes. 
105' 
4-055 

Excess  of  crop  over  ) 
seed                ...     C 

3-9 

52-82 

70-213 

100-945 

What  strikes  us  here  at  once  is  the  great  difference 
in  the  number  and  weight  of  the  seeds  respectively 
gathered  from  the  several  pots.  The  soil  richer  in 
nutritive  substances  yielded  not  only  more,  but  larger 
and  heavier  seeds,  the  average  weight  in  milligrammes 
being  respectively  : — • 


1st  Pot. 

2d  Pot. 

3d  Pot. 

4th  Pot. 

milligr. 
793 

milligr. 
776 

milligr. 
817 

milligr. 
813 

One  of  the  gathered  beans  weighed.  . 

564 

718 

917 

1019 

Of  the  seeds  of  the  plants  grown  in  the  first  pot 
(pure  turf),  seven  weighed  no  more  than  five  of  the 
beans  originally  sown ;  whereas  those  of  -the  plants 
grown  in  the  saturated  turf  weighed  each  l-5th  more 
than  one  of  the  seed-beans. 

If  we  compare  the  crop  of  seeds  with  the  quantity 
of  nutritive  substances  contained  in  the  turf  of  the  four 
pots,  we  see  at  once  what  influence  the  form  and  distri- 
bution of  the  nutritive  substances  have  exercised  upon 
their  nutritive  power. 


116 


THE   SOIL. 


The  l-4th  saturated  turf  contained  a  little  above 
one-half  (0*83  gramme)  more  phosphoric  acid  than  that 
in  the  pure  turf  (1*586  grammes) ;  the  potash  was 
doubled ;  and  the  amount  of  nitrogen  was  increased 
only  by  ^Tth.  The  'crop,  however,  exceeded  that  ob- 
tained from  the  plants  grown  in  pure  turf,  not  by  ^d 
(corresponding  to  the  quantity  of  phosphoric  acid 
added),  but  it  was  thirteen  times  as  large.  The  feeble 
manuring  had  caused  the  turf  in  the  second  pot  to  ren- 
der thirteen  times  more  nutritive  matter  for  the  forma- 
tion of  seed  alone,  and  for  the  entire  plants  about  thirty 
times  more  than  the  pure  turf. 

It  is  evident  that  only  a  small  proportion  of  the  ash- 
constituents  in  the  pure  turf  were  present  in  a  form 
suitable  for  the  nutrition  of  the  bean-plant.  They  could 
not  be  absorbed,  because  they  were  in  chemical  combi- 
nation in  the  substance  of  the  turf.  To  use  a  somewhat 
imperfect  figure,  the  nutritive  elements  in  the  pure  turf 
may  be  imagined  to  be  surrounded  by  the  turfy  sub- 
stance, which  hinders  their  contact  with  the  roots ; 
while  in  the  saturated  turf  these  elements  form  the 
outer  coating  of  the  turfy  substance. 

The  crops  of  seeds  show  further  that  they  were  not 
in  proportion  to  the  nutritive  substances  contained  in 
the  soil,  but  that  the  poorer  mixture  yielded  far  more 
seeds  than  it  should  have  done  in  proportion  to  the 
production  of  the  richer  mixtures.  The  proportions  in 
the  several  mixtures  were  as  follows  : — 


2d  Pot, 
quar.  saturated. 

3d  Pot, 
half  saturated. 

4th  Pot, 
fully  saturated. 

Amount  of  manure           •  . 

1 

2 

4 

2 

2-8 

4 

It  is  not  difficult  to  understand  why  this  should  be 
so.  The  fact  that  the  J-saturated  turf  yielded  twice  as 
much  crop  as  corresponded  to  the  amount  of  manure, 
proves  that  the  absorbent  root-surface  had  come  in  con- 
tact with  double  the  number  of  nutritive  turf  particles. 


RELATION   OF   CROP   TO   FOOD   IN   SOIL. 

According  to  weight,  the  ^-saturated  turf  contained,  in 
every  cubic  centimetre,  only  Jth  of  the  nutritive  sub- 
stances found  in  the  completely  saturated  turf ;  but,  by 
mixing  1  volume  of  saturated  with  3  volumes  of  unsat- 
urated  turf,  the  former  had  become  far  more  distrib- 
uted, and  its  volume  or  efficient  surface  had  been  made 
larger.  Supposing  it  were  possible  to  coat  3  volumes 
of  ordinary  turf-powder  with  1  volume  of  saturated,  so 
as  completely  to  surround  every  fragment  of  the  former 
with  saturated  turf  particles,  the  bean-plants  would,  in 
a  soil  so  prepared,  grow  as  luxuriantly  as  if  every  par- 
ticle of  the  turf  were  thoroughly  saturated  with  nutri- 
tive substances. 

Hence,  the  higher  produce  obtained  from  the  com- 
paratively poorer  soil  proves  that  it  is  only  the  surface 
of  the  soil,  containing  the  nutritive  elements,  which  is 
effective  ;  that  the  fertility  of  a  soil  is  not  proportionate 
to  the  quantity  of  nutritive  substances  which  chemical 
analysis  proves  to  be  present ;  and  lastly,  these  facts 
show  that  it  is  not  water  which,  by  virtue  of  its  solvent 
power,  has  made  the  nutritive  elements  available  to  the 
roots. 

We  know  by  experiment,  that  when  water  has  dis- 
solved from  a  saturated  soil  a  certain  quantity  of  am- 
monia, potash,  &c.,  the  same  amount  of  water  will  not 
further  dissolve  from  a  half-saturated  soil  (or  a  soil  from 
which  one-half  of  the  absorbed  potash  and  ammonia  has 
already  been  extracted)  half  so  much  as  from  the  sat- 
urated soil ;  but  that  the  earth,  in  proportion  as  it  has 
thus  become  poorer  in  nutritive  substances,  will  all  ,the 
more  firmly  retain  the  residue  of  the  ingredients  ab- 
sorbed by  it. 

In  the  half-saturated  turf  the  nutritive  elements  are 
much,  more  firmly  bound  than  in  the  fully  saturated ; 
and,  again,  in  the  quarter-saturated  much  more  firmly 
than  in  the  half-saturated. 

Hence,  even  if  the  water  had  been  able  to  dissolve 
and  convey  to  the  roots  half  as  much  from  the  half- 
saturated  as  from  the  fully  saturated,  and  half  as  much 
from  the  quarter-saturated  as  from  the  half-saturated, 


118  THE   SOIL. 

still  the  produce  could  not  in  any  case  be  greater  than 
in  proportion  to  the  amount  of  nutritive  substances  in 
the  soil.  But,  in  fact,  they  were  far  greater,  and  the 
roots  actually  absorbed  more  nutritive  substances  than 
the  water  could  possibly  have  conveyed  to  thorn,  even 
under  the  most  favourable  circumstances. 

These  experiments  have,  for  the  first  time,  afforded 
direct  proof  that  plants  possess  the  power  of  absorbing 
their  necessary  nutritive  elements  from  a  soil  in  which 
they  are  present  in  physical  combination,  i.e.  in  a  state 
wherein  they  have  lost  their  solubility  in  water ;  and 
the  comportment  of  arable  and  cultivated  soil  in  general 
shows  that  the  nutritive  substances  contained  in  them 
must  be  present  in  the  same  form  as  in  the  artificial 
turf  soil  of  these  experiments,  with  this  difference,  how- 
ever, that  the  earthy  particles  in  the  arable  soil  are 
not  merely  the  vehicles  of  these  substances,  but  their 
source.  In  a  soil  consisting  of  turf-powder,  a  second 
crop  will  not  succeed  so  well  as  the  first,  unless  the 
nutritive  substances  which  have  been  removed  are 
again  supplied ;  nor  will  the  soil  regain  its  fertility, 
however  long  it  be  left  fallow. 

The  benefit  derived  from  mechanical  tillage  of  the 
ground  depends  upon  the  law,  that  the  nutritive  sub- 
stances existing  in  a  fruitful  soil  are  not  made  to  change 
their  place  by  the  water  circulating  in  it ;  that  the  cul- 
tivated plants  receive  their  food  principally  from  the 
earthy  particles  with  which  the  roots  are  in  direct  con- 
tact, out  of  a  solution  forming  around  the  roots  them- 
selves ;  and  that  all  nutritive  substances  lying  beyond 
the  immediate  reach  of  the  roots,  though  in  themselves 
quite  effective  as  food,  are  not  directly  available  for  the 
use  of  the  plants. 

There  are  no  isolated  laws  in  nature,  but  they  are 
all  together  links  in  one  chain  of  laws,  which  are  in 
turn  subordinate  to  a  higher  and  a  highest  law. 

"With  the  natural  law,  that  organic  life  is  developed 
only  in  the  outermost  crust  of  the  earth  which  is  ex- 
posed to  the  sun,  is  most  intimately  connected  the 
power  of  the  fragments  of  that  crust  which  form  the 


FIXED    STATE    OF   FOOD   OF   PLANTS    IN    THE    SOIL/     119 

arable  surface  soil,  to  collect  and  retain  all  those  nutri- 
tive substances  on  which  life  depends.  A  plant  is  not, 
like  an  animal,  endowed  with  special  organs  to  dissolve 
the  food  and  make  it  ready  for  absorption ;  this  prep- 
aration of  the  nutriment  is  assigned  by  another  law  to 
the  fruitful  earth  itself,  which  in  this  respect  discharges 
the  functions  performed  by  the  stomach  and  intestines 
of  animals.  The  arable  soil  decomposes  all  s.alts  of 
potash,  of  ammonia,  and  the  soluble  phosphates ;  and 
the  potash,  ammonia,  and  phosphoric  acid  always  take 
the  same  form  in  the  soil,  no  matter  from  what  salt 
they  are  derived.  In  performing  this  function,  the 
plant-bearing  earth  constitutes  for  the  use  of  man  and 
beast  an  immense  purifying  apparatus,  whereby  it 
removes  from  the  water  all  matters  hurtful  to  the 
health  of  animals,  and  all  products  resulting  from  the 
decay  and  putrefaction  of  deceased  generations  of  plants 
and  animals. 

The  question  how  much  of  the  several  nutritive  sub- 
stances a  soil  must  contain  to  yield  remunerative  crops 
is  of  great  importance,  but  its  exact  determination  is 
beset  with  vast  difficulties.  If,  indeed,  the  nutritive 
power  of  an  arable  soil  depends  upon  the  quantity  of 
substances  held  in  physical  combination  in  the  ground, 
it  is  evident  that  a  chemical  analysis,  which  cannot 
rigorously  distinguish  elements  in  chemical  combina- 
tion from  those  in  physical  combination,  must  fail  to 
afford  any  certain  conclusion  in  the  matter. 

In  comparing  several  equally  productive  soils,  we 
often  find  that  they  differ  immensely  in  their  chemical 
composition ;  and  that  of  two  soils  containing,  the  one  80 
to  90  per  cent.,  the  other  only  20  per  cent,  of  pebbles 
and  sand,  the  former  will  frequently  yield  better  crops 
than  the  latter.  The  case  is  possible,  that  a  soil  fruitful 
in  itself  may  not  suffer  any  diminution  of  its  fertility  by 
being  mixed  with  half  its  volume  of  sand,  but  may 
actually  become  more  productive,  though  it  now  con- 
tains, in  every  part  of  its  transverse  section,  one-third 
less  nutritive  matter  than  before.  The  reason  is,  that 
by  the  addition  of  sand  the  food-affording  surface  of  the 


120  THE   SOIL. 

other  constituent  parts  of  the  soil  is  enlarged,  and  on 
this  everything  depends  as  regards  the  power  of  the  soil 
to  give  up  to  plants  the  food  contained  in  it. 

A  soil  on  which  rye  thrives  well  often  proves  un- 
suited  for  the  profitable  cultivation  of  wheat,  though 
both  plants  take  from  the  soil  exactly  the  same  con- 
stituents. 

It  is  clear  that  the  failure  of  wheat  on  such  a  soil 
arises  from  this  cause,  that  the  wheat  plants,  within  the 
allotted  period  of  their  existence,  do  not  find  nutriment 
enough  for  their  full  developement  in  the  food-supplying 
soil  about  their  roots,  whilst  the  quantity  supplied  is 
ample  for  the  rye  plants. 

Now  chemical  analysis  proves  that  such  a  rye  soil 
altogether  contains,  to  a  depth  of  5  to  10  inches,  fifty — 
nay,  a  hundred  times  more  of  the  food-elements  of  the 
wheat  plant  than  would  be  required  for  an  abundant 
crop  of  wheat ;  and  yet,  in  spite  of  this  superabundance, 
the  field  will  afford  no  remunerative  crop  to  the  agri- 
culturist. 

If  we  compare  the  quantities  of  phosphoric  acid  and 
potash  drawn  from  an  area  of  2^  acres  (hectare),  by  an 
average  wheat  crop  (2000  kilogrammes=4400  Ibs.  of 
grain,  and  5000  kilogrammes^  11000  Ibs.  of  straw)  and 
a  rye  crop  (1600  kilogrammes— 3520  Ibs.  of  grain  and 
3800  kilogrammes =83 60  Ibs.  of  straw),  we  find  that 
the  two  crops  severally  received  from  the  soil — 


Wheat. 

Eye. 

Phosphoric  acid    

Kilogr.       Ibs.       Ibs. 
25  —  26—  55  to  57 

Kilogr.         Ibs.      Ibs. 
17  —  18—   37  to  39 

Potash     .  . 

52  —  114 

39  —  40—  86  —  88 

Silicic  acid.     ...       ... 

160—352 

100  —  110—220  —  242 

The  difference  in  the  absolute  requirement  is  there- 
fore very  small.  The  wheat  crop  received  from  the  soil 
only  9  kilogrammes  (=20  Ibs.)  of  phosphoric  acid,  about 
12  kilogrammes  (=26*4  Ibs.)  of  potash,  and  50  to  60 


WHY   KYE   MAY    FLOURISH   AND   NOT    WHEAT.          121 

kilogrammes  (=110  to  132  Ibs.)  of  silicic  acid,  more 
than  the  rye  crop. 

Before  the  true  cause  was  known  upon  which  the 
nutritive  power  of  arable  soil  depends,  it  was  utterly 
incomprehensible  how  this  trifling  difference  of  a  few 
pounds  of  phosphoric  acid,  silicic  acid,  and  potash  in 
the  requirements  of  wheat  and  rye,  could  make  so  great 
a  difference  in  the  quality  of  a  field  ;  for  in  comparison 
with  the  total  amount  of  these  ingredients  actually  con- 
tained in  the  rye  field,  the  additional  quantity  required 
by  the  wheat  plant  is  inappreciably  small. 

This  difference  would  indeed  be  inconceivable  if  the 
nutritive  substances  required  by  the  cereal  plants  had 
any  perceptible  power  of  locomotion,  for  in  that  case 
there  could  not  be  an  actual  deficiency  of  food  in  any 
given  spot  of  the  soil ;  every  fall  of  rain  would  provide 
the  poorer  places  with  nutriment,  if  the  trifling  excess 
required  by  the  wheat  above  the  rye  could  really  be 
distributed  by  the  agency  of  water. 

Thus,  although  a  soil  suited  for  rye  but  not  for 
wheat,  may  contain,  within  a  short  distance  from  the 
roots  of  the  wheat,  a  large  quantity  of  phosphoric  acid 
and  potash,  often  amounting,  in  the  volume  of  earth 
between  two  rye  plants,  to  fifty  times  more  than  the 
trifling  addition  demanded  by  the  wheat,  yet,  in  point 
of  fact,  this  nutriment  cannot  reach  the  roots  of  the 
latter. 

But  if  we  consider  that  the  nutritive  substances  can- 
not of  themselves  change  their  place  in  the  ground,  the 
failure  of  wheat  upon  a  rye  field  is  very  simply  ex- 
plained. 

If  a  2^-  acre  field  yields  to  an  average  rye  crop 
(grain  and  straw)  17  million  milligrammes  (— 37 '4  Ibs.) 
of  phosphoric  acid,  39  million  milligrames  (=85'8 
Ibs.)  of  potash,  and  102  million  milligrammes  (=224*4: 
grains)  of  silicic  acid,  then  the  rye  plants  growing  on  a 
square  decimetre  (=15*3  square  inches)  receive  from 
the  soil  17  milligrammes  (=0'26  grains)  of  phosphoric 
acid,  39  milligrammes  (=0'6  grain)  of  potash,  and  102 
milligrammes  (=1*56  grains)  of  silicic  acid. 


122  THE    SOIL. 

Now,  from  the  same  area  of  a  good  wheat  soil,  the 
wheat  plants  growing  on  it  receive  26  milligrammes  of 
phosphoric  acid,  52  milligrammes  of  potash,  and  160 
milligrammes  of  silicic  acid.  The  food-absorbent  sur- 
face of  the  rye  and  wheat  plants  is  not  in  contact  with 
all  the  earthy  particles  which  contain  food  in  a  square 
decimetre  of  the  field  downwards,  but  only  with  a  small 
volume  of  the  soil ;  and  it  is  quite  evident,  that  if  the 
seed  is  to  thrive  in  every  spot,  the  earthy  particles, 
which  do  not  happen  to  come  in  contact  with  the  roots, 
must  contain  as  much  nutritive  matter  as  the  others. 

If  we  could  ascertain  with  any  certainty  the  root- 
surface  which  absorbs  nutriment,  we  might  infer  the 
volume  of  earth  from  which  it  received  food,  for  every 
root-fibre  is  surrounded  by  a  cylinder  of  earth,  the  inner 
wall  of  which  facing  the  root  is 'as  it  were  gnawed  off  by 
the  extremities  of  the  root  which  press  downwards,  or 
by  the  cell-surfaces  which  are  deposited  in  a  downward 
direction.  But  in  no  plant  are  the  diameter  and  length 
of  the  root-fibres  determined,  and  we  must  rest  satisfied 
with  an  approximative  estimation. 

Let  us  assume  that  the  17  milligrammes  (=0*26  gr.) 
of  phoshporic  acid,  39  milligrammes  (=0*6  gr.)  of  pot- 
ash, and  102  milligrammes  (=1*56  grs.)  of  silicic  acid, 
are  absorbed  from  a  mass  of  earth  the  transverse  sec- 
tion of  which  is  100  square  millimetres  (—15*3  square 
inches),  then  the  rye-field  in  each  square  decimetre 
(10,000  square  millimetres)  will  contain  1700  milli- 
grammes (  =  26 '2  grs.)  of  phosphoric  acid,  3900  milli- 
grammes (  =  60  grs.)  of  potash,  and  10,200  milli- 
frammes  (  =  15*7  grs.)  of  silicic  acid ;  that  is,  a  hun- 
red  times  as  much  as  an  average  rye  crop  requires. 
Now,  as  the  wheat  plant,  to  thrive  equally  well,  must 
receive  half  as  much  again  of  phosphoric  and  silicic 
acid,  and  0*4  more  potash,  from  the  same  portions  of 
the  soil,  it  follows  that  if  a  hectare  (2J  acres),  to  produce 
an  average  rye  crop,  contains 

1700  kilogrammes  =    3740  Ibs.  of  phosphoric  acid, 
3900  "  =    8580    "          potash,  and 

10200  "  =  22440    "         silicic  acid, 


ESTIMATION    OF   FOC^D   IN    A   WHEAT    SOIL.  123 

a  fertile  .wheat  soil  must  contain 

2560  kilogrammes  =    5632  Ibs.  of  phosphoric  acid, 
5200  =  11440    "          potash,  and 

15300  "  =  33660    "          silicic  acid, 

If  a  cubic  decimetre  (1  litre  =  1'T  pint)  of  arable 
soil  weighs  on  an  average  1200  grammes  (  =  2 '64  Ibs.), 
and  we  assume  that  the  greater  number  of  the  roots  of 
a  wheat  plant  do  not  go  deeper  than  25  centimetres  (10 
inches),  then  the  above  1700  milligrammes  of  phos- 
phoric acid,  3900  milligrammes  of  potash,  and  10,200 
milligrammes  of  silicic  acid,  must  be  contained  in  an 
available  form  in  2-J  cubic  decimetres,  or  3000  grammes 
(  =  66  Ibs.)  of  soil :  this  makes  0-056  per  cent,  of  phos- 
phoric acid,  0-034  per  cent,  of  potash,  and  0-34  per 
cent,  of  silicic  acid. 

Before  we  discuss  the  inferences  which  follow  from 
these  numbers,  we  must  remember  that  they  involve 
some  hypothetical  elements,  which  ought  not  to  be  left 
out  of  view.  The  numbers  representing  the  quantity 
of  ash  constituents,  which  an  average  rye  and  wheat 
crop  take  from  a  hectare  (2|-  acres)  in  corn  and  straw, 
have  been  determined  by  chemical  analysis,  and  are 
not  hypothetical.  It  is  therefore  certain  that  a  wheat 
crop  draws  from  the  ground  half  as  much  again  of 
phosphoric  acid  and  silicic  acid,  and  one-third  more 
potash,  than  a  rye  crop. 

The  supposition  that  a  wheat  soil,  to  the  depth  of 
10  inches,  contains  in  physical  combination  0.056  per 
cent,  of  phosphoric  acid,  0-034  per  cent,  of  potash,  and 
0-34:  per  cent,  of  silicic  acid,  which  makes  a  hundred 
times  as  much  as  a  wheat  crop  would  take  in  corn  and 
straw  from  the  field,  is  purely  hypothetical ;  and  the 
present  question  is  to  determine  the  limits  up  to  which 
this  estimate  may  be  accepted  as  true. 

If  arable  soil  is  left  for  twenty-four  hours  in  contact 
with  cold  muriatic  acid,  a  certain  quantity  of  potash, 
phosphoric  acid,  silicic  acid,  as  well  as  lime,  magnesia, 
&c.  is  extracted.  If  the  soil  is  treated  for  a  long  time 
with  loiling  muriatic  acid,  the  quantities  of  dissolved 
silicic  acid  and  potash  are  much  greater.  Lastly,  by 


124: 


THE    SOIL. 


decomposing  by  fusion  the  silicates,  and  then  treating 
with  hot  muriatic  acid,  we  can  obtain  all  the  potash 
and  silicic  acid  contained  in  the  soil.  Without  risk  of 
error  we  may  assume  that  those  nutritive  substances 
which  can  be  extracted  by  cold  muriatic  acid  are  most 
feebly  retained  by  the  soil,  and  approach  nearest  the 
elements  in  physical  combination ;  or,  at  all  events,  so 
near,  that  by  the  common  disintegrating  agencies  they 
very  easily  pass  into  this  form  of  combination. 

In  this  way  Dr.  Zoeller  subjected  to  analysis  two 
kinds  of  wheat  soil — the  loam  of  Bogenhausen  and  of 
"Weihenstephan,  the  latter  of  which  in  particular  repre- 
sents an  excellent  wheat  soil.  One  hundred  parts  of 
these  two  soils  yielded  to  cold  muriatic  acid — 


Phosphoric  acid. 

Potash. 

Silicic  acid. 

Soil  of  Wcihcnstephan  . 

0-219 

0249 

0-596 

0'129 

0-093 

0-674 

If  these  quantities  of  nutritive  elements  are  present 
in  an  available  condition  in  these  soils,  that  of  "Weihen- 
stephan  would  contain  of  phosphoric  acid  almost  400 
times,  of  potash  TOO  times,  and  of  silicic  acid  rather 
more  than  190  times,  as  much  as  a  wheat  crop  re- 
quires :  in  the  soil  of  Bogenhausen  the  amount  of  phos- 
phoric acid,  potash,  and  silicic  acid  would  be  twice  as 
large  as  the  hypothesis  presupposed. 

The  wrell-known  analyses  of  similar  soils  by  other 
chemists  show  that  the  assumed  estimate  of  the  nutri- 
tive substances  required  in  a  good  wheat  or  rye  soil  is 
rather  below  than  above  the  actual  amount ;  and,  in 
fact,  the  future  prospects  of  agriculture  would  be  very 
gloomy,  if  the  ground  was  not  far  richer  in  nutritive 
substances  than  has  here  been  hypothetically  assumed. 

This  is,  perhaps,  the  place  to  state  the  distinction 
between  the  fertility  of  a  field  and  its  productive  pow- 
ers. According  to  the  experiments  of  Nageli  and  Zoel- 
ler, mentioned  above,  the  turf  maybe  so  saturated  with 
the  necessary  nutritive  substances  as  to  become  an  ex- 


NATURE   OF   A   KYE    SOIL.  125 

tremely  fruitful  soil  for  beans ;  and  a  comparison  of 
the  ash  constituents,  in  the  stalks  and  seeds  of  the  crop, 
with  the  quantity  which  had  been  added  to  the  turf, 
shows  that  the  twelve  to  fourteen-fold  quantity  of  these 
ash  constituents  was  enough  to  produce  a  very  abun- 
dant seed  crop.  The  porous  turf,  saturated  even  in 
its  minutest  particles  with  nutritive  elements,  favoured 
in  this  case  an  enormous  developement  of  the  roots,  to 
which  the  largeness  of  the  crops  is  due.  Nothing  can 
be  more  certain  than  that  its  power  of  production 
measured  by  time  is  very  small,  and  that  after  a  very 
few  harvests  its  fertility  would  vanish  speedily  and  for 
ever. 

That  our  corn  fields  should  contain  nutritive  sub- 
stances in  very  great  abundance  is  the  necessary  condi- 
tion for  &  continuance  of  good  crops,  but  it  is  not  indis- 
pensable for  one  rich  harvest. 

A  good  rye  soil  is  one  which  produces  an  average 
rye  crop,  but  less  than  an  average  wheat  crop. 

From  what  we  have  seen,  the  reason  why  a  wheat 
plant,  which  requires  from  the  soil  the  same  elements 
as  the  rye  plant,  will  not  thrive  as  well  as  the  latter 
upon  a  rye  soil,  is  founded  on  this,  that  during  the 
same  period  of  time  the  wheat  needs  more  of  these  nu- 
tritive substances  than  the  rye,  but  cannot  obtain  this 
additional  quantity.  Hence,  a  good  wheat  soil  which 
yields  an  average  wheat  crop,  differs  from  a  good  rye 
soil  which  produces  an  average  rye  crop,  inasmuch  as 
the  wheat  soil  in  all  its  parts  contains  more  nutritive 
substances,  just  in  proportion  as  the  wheat  crop  needs 
and  carries  away  more  than  the  rye  crop. 

A  good  rye  soil,  which  is  able  to  give  and  does  give 
1  per  cent,  of  its  nutritive  substances  to  an  average  rye 
crop,  would  necessarily  yield  an  average  wheat  crop,  if 
the  wheat  plants  growing  upon  it  could  extract  1-J-  per 
cent,  of  its  nutriment.  But,  in  fact,  this  does  not  take 
place :  whence  it  follows  that  the  absorbent  root-sur- 
faces of  the  wheat  cannot  be  half  as  large  again  as 
those  of  the  rye ;  for,  were  this  the  case,  the  roots  of 
the  wheat  would  come  into  contact  with  half  as  many 


126  THE   SOIL. 

more  earthy  particles  yielding  nutriment,  i.  e.  the  rye 
soil  would  necessarily  produce  an  average  wheat  crop, 
which  however  is  not  the  case. 

The  comparative  returns,  in  corn  and  straw,  from  a 
rye  soil,  which  has  been  sown  simultaneously  half  with 
wheat  and  half  with  rye,  might  therefore  enable  us  to 
estimate  the  extent  of  root  surface  in  wheat  and  rye 
plants.  If  the  wheat  crop  from  one-half  of  such  a 
field,  reckoning  by  the  hectare,  receives  as  much  phos- 
phoric acid  and  potash  as  the  rye  crop  from  the  other 
half  (17  kilogrammes  of  phosphoric  acid  and  39  kilo- 
grammes of  potash),  this  would  argue  that  the  roots  of 
the  wheat  have  come  in  contact  with  earth  yielding  as 
much  nutritive  substance,  and  the  earth- with  the  same 
extent  of  absorbent  root  surfaces,  as  in  the  case  of  the 
rye.  If  the  wheat  crop  contains  phosphoric  acid,  pot- 
ash, and  silicic  acid,  either  more  or  less  than  the  rye 
crop,  this  would  lead  us  to  infer  a  larger  or  smaller 
ramification  of  the  roots.  Experiments  of  this  kind 
with  rye,  wheat,  barley,  and  oats  are  well  worth  mak- 
ing, although  they  have  no  practical  interest  for  the 
farmer,  but  merely  a  physiological  importance,  and 
would  finally  lead  to  conclusions,  the  correctness  of 
which  lies  within  rather  wide  limits.  The  absorptive 
power  of  the  plant,  and  the  time  of  absorption,  make  a 
difference  which,  however,  hereby  becomes  perceptible. 

Of  two  plants,  with  the  same  absorbent  root  surface, 
and  yielding  equal  produce,  one  of  which  flowers  and 
ripens  earlier  than  the  other,  the  one  with  the  shorter 
period  of  vegetation  must  find  somewhat  more  food,  in 
all  the  places  which  furnish  its  nutriment,  in  order  to 
receive  the  same  amount  as  the  other,  which  has  a 
longer  time  for  absorption. 

Thus,  the  only  hypothetical  assumptions  in  deter- 
mining the  above  numbers  are,  that  the  food-absorbent 
root  surfaces  of  rye  and  wheat  are  equal,  and  that  the 
rye  soil  yields  neither  more  nor  less  than  exactly  1  per 
cent,  of  its  nutritive  substances.  No  doubt  such  a  soil 
has  no  actual  existence ;  but,  supposing  that  we  had 
such  a  soil  before  us,  and  were  to  put  the  question  how 


CONVERSION    OF   EYE   INTO    WHEAT    SOIL. 


127 


much  nutriment  we  must  add  to  convert  it  into  a  per- 
manently productive  wheat  soil,  the  answer  would  be 
not  hypothetical,  but  perfectly  trustworthy  and  exact. 
If 


Phosphoric  acid. 

Potash. 

Silicic  acid. 

Kilogr. 
2560 

Kilogr. 
5200 

Kilogr. 
15300 

The  rye  soil  

1700 

3900 

10200 

The  wheat  soil  is  the  richer  of  ) 
the  two  by  .                .       .    \ 

860 

1300 

5100 

Hence,  to  a  rye  soil  of  a  given  condition  and  productive 
power,  we  should  have  to  add,  in  some  form  or  other, 
one-half  more  phosphoric  and  silicic  acid,  and  one-third 
more  potash,  than  it  already  contains,  to  make  it  capa- 
ble of  producing  average  crops  of  wheat  grain  and 
straw. 

And  to  obtain  permanently  from  a  wheat  soil  a 
crop  half  as  large  again  as  an  average  harvest,  we 
should  add  one-half  more  of  nutritive  substances  than 
it  already  contains. 


Phosphoric  acid. 

Potash. 

Silicic  acid. 

A  hectare  of  wheat  soil  contains 
One-half  more  

Kilogr. 
2560 
1280 

Kilogr. 
5200 
2600 

Kilogr. 
10200 
5100 

3840 

7800 

15300 

These  speculations  have  no  other  object  than  to 
show  that  a  small  difference  in  the  absolute  quantity  of 
a  nutritive  element,  required  by  one  kind  of  plant  more 
than  by  another,  presupposes  a  great  excess  in  the 
amount  of  this  constituent  in  the  soil.  A  wheat  crop 
takes  from  the  soil,  per  hectare  (2-J  acres),  only  8*6  kil- 
ogrammes (19  Ibs.)  more  phosphoric  acid  than  a  rye 
crop  ;  but  that  the  wheat-roots  may  appropriate  these 
8*6  kilogrammes,  the  soil  must  contain  a  hundred  times 


128  THE   SOIL. 

as  much  (860  kilogrammes)  of  phosphoric  acid  as  the 
rye  soil,  or  perhaps  even  more. 

Although  these  figures  refer  to  an  ideal  soil  of 
strictly  definite  composition,  yet  the  conclusion  which 
we  draw  is  true  for  all  classes  of  soil. 

It  is  an  undoubted  fact,  that  the  ground  must  al- 
ways, and  under  all  circumstances,  contain  a  larger 
amount  of  nutritive  substances  than  the  crop  grown  on 
it.  Supposing  the  soil  to  contain,  instead  of  the  hun- 
dred-fold, only  the  seventy  or  fifty -fold  quantity  of  the 
nutritive  elements  in  the  crop,  we  infer  from  the  law 
of  the  immobility  of  these  elements,  that,  to  double  the 
crop,  we  must  add  to  the  field  seventy  or  fifty  times 
the  quantity  of  mineral  constituents  contained  in  the 
produce.  In  practice  the  case  is  different,  for  no  actual 
field,  like  our  ideal  one,  contains  phosphoric  acid,  pot- 
ash, and  silicic  acid  in  exactly  the  relative  proportions 
in  which  they  exist  in  the  ash  of  rye  or  wheat.  Most 
fields  which  are  suitable  for  cereals  are  fruitful  also  for 
potatoes,  clover,  or  turnips,  which  extract  from  the  soil 
much  more  potash  than  the  cereals. 

Therefore  to  convert  a  rye  soil  containing  more  than 
3900  kilogrammes  of  potash,  per  hectare  (2-J-  acres),  into 
a  wheat  soil,  would  not  require  an  addition  of  1300 
kilogrammes  of  potash,  but  a  proportionately  less 
amount  would  fully  answer  the  purpose. 

"We  shall  hereafter  discuss  at  greater  length  the  re- 
lations existing  between  the  composition  of  a  soil  and 
its  fertility.  The  main  conclusion,  which  the  above  fig- 
ures are  intended  to  illustrate,  is  the  practical  impossi- 
bility of  converting  a  rye  soil  into  a  wheat  soil  by  supply- 
ing the  deficient  ash  constituents,  or  of  making  a  wheat 
field  by  the  same  means  produce  half  as  much  again  as 
an  average  crop.  Admitting  this  might  be  readily  ac- 
complished, .experimentally,  on  a  small  area,  yet  the 
price  of  phosphoric  acid,  potash,  or  even  of  soluble  silica, 
and  the  impossibility  of  procuring  them  for  a  large  num- 
ber of  fields,  though  in  a  given  field  only  one  of  these 
substances  had  to  be  increased  in  the  proportion  stated, 


PRODUCTIVE   POWER   OF  EACH   SOIL   VARIES.          129 

would  oppose  insuperable  obstacles  to  the  conversion 
or  improvement  of  land. 

The  law  of  the  immobility  of  the  mineral  elements 
in  the  soil  explains  the  agricultural  experience  of  ages, 
that  almost  universally,  under  like  climatic  conditions, 
certain  fields  are  suited  for  certain  plants  only,  and 
that  no  plant  can  be  profitably  cultivated  upon  a  soil, 
unless  the  mineral  contents  of  the  soil  are  in  proportion 
to  the  special  requirements  of  that  plant. 

In  practice,  it  is  quite  impossible,  by  a  supply  of 
mineral  substances,  to  improve  the  land  of  an  entire 
country,  so  that  it  shall  yield  crops  considerably  more 
abundant  than  the  natural  store  of  food  elements  in  the 
soil  enables  it  to  produce. 

Every  field  has  a  real  and  an  ideal  maximum  of 
productive  power  corresponding  to  the  nutritive  sub- 
stances which  it  contains.  Under  the  most  favourable 
cosmical  conditions,  the  real  maximum  corresponds  to 
that  portion  of  the  total  amount  of  nutritive  elements, 
which  is  present  in  the  soil  in  an  available  form,  i.  e. 
in  a  state  of  physical  combination  with  the  soil ;  the 
ideal  maximum  is  what  might  possibly  be  obtained  if 
the  rest  of  the  nutritive  substances,  which  are  in  chem- 
ical combination,  were  converted  into  an  available 
form,  and  distributed  through  the  soil. 

Hence,  the  art  of  the  agriculturist  mainly  consists 
in  selecting  such  plants  as  will  thrive  best  on  his  land, 
in  adopting  a  proper  system  of  rotation,  and  in  using 
all  the  means  at  his  command  to  make  the  nutritive 
elements  in  chemical  combination  available  for  plants. 

The  achievements  of  practical  agriculture  in  these 
respects  are  wonderful,  and  they  demonstrate  that  the 
triumphs  of  art  far  exceed  those  of  science,  and  that 
the  farmer,  by  aiding  the  agencies  which  improve  the 
chemical  and  physical  condition  of  his  land,  can  obtain 
much  more  abundant  crops  than  by  supplying  nutritive 
matters.  Because,  what  he  can  supply  in  the  shape  of 
manure,  with  due  regard  to  a  proper  return,  is  so  small 
in  comparison  with  the  store  of  nutritive  matter  con- 


130  THE   SOIL. 

tained  in  a  fruitful  soil,  that  a  perceptible  pincrease  of 
produce  can  hardly  be  expected  to  result  from  it. 

But  what  the  farmer  may  achieve  by  manuring  is 
at  best  the  result — unquestionably  a  most  important 
one — that  his  crops  suffer  no  diminution.  "Where  they 
actually  increase,  this  is  less  attributable  to  the  addi- 
tion made  to  the  store  of  mineral  constituents  than  to 
their  distribution,  and  to  the  fact  that  certain  quantities 
of  inoperative  substances  have  been  rendered  available. 

If  we  wished,  by  increasing  the  phosphoric  acid  re- 
quired for  the  formation  of  seed,  to  enable  a  wheat-field 
yielding  an  average  produce  of  sk  grains  to  give  two 
additional  grains,,  it  would  be  necessary  to  increase  by 
^rd  the  whole  amount  of  the  phosphoric  acid  present  in 
the  field,  and  serving  for  the  formation  of  seed.  For  it 
is  always  but  a  small  fraction  of  the  total  quantity  sup- 
plied that  comes  into  contact  with  the  roots  of  the 
plants  ;  and  that  they  may  be  able  to  absorb  this  -Jrd 
more,  it  is  indispensably  necessary  to  increase  the  phos- 
phoric acid  by  -Jrd  in  all  portions  of  the  soil.  This  re- 
flection explains  the  rule  found  true  in  experience,  that 
to  produce  a  marked  effect  upon  crops  by  manuring,  a 
mass  of  manure  must  be  laid  on,  utterly  disproportion- 
ate to  the  expected  increase. 

A  manure  will  exercise  its  beneficial  action  upon  a 
field  in  the  most  marked  manner,  when  it  establishes  a 
more  suitable  relative  proportion  between  the  several 
mineral  constituents  in  the  soil ;  because  upon  this  pro- 
portion the  crops  are  dependent.  ~No  special  argument 
is  needed  to  demonstrate,  that  where  a  wheat  soil  con- 
tains just  so  much  phosphoric  acid  and  potash  as  will 
suffice  to  afford  the  quantity  of  these  two  substances 
required  for  a  full  wheat  crop,  and  no  more  (accord- 
ingly for  every  part  by  weight  of  phosphoric  acid  two 
parts  by  weight  of  potash),  an  additional  supply  of  one- 
half  more,  or  even  of  double  the  quantity  of  potash, 
cannot  exercise  the  slightest  possible  influence  upon 
the  crop  of  corn.  •  The  wheat-plant  requires  for  its  full 
developement  a  certain  relative  proportion  of  both  nu- 
tritive substances,  and  any  increase  of  one  beyond  this 


RELATIONS   EXISTING   AMONG    FOOD   ELEMENTS.        131 


proportion  makes  the  other  not  a  whit  more  effective, 
because  the  additional  supply  exercises  by  itself  no 
action. 

An  increase  of  phosphoric  acid  alone  has  just  as 
little  influence  in  making  the  returns  greater,  as  an  in- 
crease of  potash  alone :  this  law  applies  equally  to 
every  nutritive  substance,  potash,  magnesia,  and  silicic 
acid ;  no  supply  of  these  substances  beyond  the  re- 
quirement of  the  wheat-plant,  or  its  capacity  of  absorp- 
tion, will  have  any  effect  upon  its  growth.  The  relative 
proportions  of  the  mineral  substances,  which  the  plants 
draw  from  the  soil,  are  easily  determined  by  analysing 
the  ashes  of  the  produce.  It  is  found  by  analysis  that 
wheat,  potatoes,  oats,  and  clover  receive  the  following 
proportions  of  phosphoric  acid,  potash,  lime,  magnesia, 
and  silicic  acid  : — 


Phosphoric 
acid. 

Potash. 

Lime  and 
magnesia. 

Bilicio  acid. 

wheat  j«|m  I   .... 

1 

2-0 

0-7 

6'7 

Potatoes  (tubers)  .... 

1 

3-2 

0-48 

0'4 

Oats      |  g^  i  

1 

2-1 

1-03 

5-0 

Clover        .         

1 

2'6 

4'0 

1*0 

Average 

1 

2-5 

1*5 

3'0 

Supposing  wheat,  potatoes,  oats,  and  clover  to  be 
cultivated  in  a  field  for  four  years  in  succession,  each 
of  these  plants  will  absorb  from  the  soil  the  proportion 
of  mineral  constituents  which  it  requires  ;  and  the  sum 
total  divided  by  the  number  of  years,  viz.  four,  shows 
the  average  relative  proportion  of  all  the  nutritive  sub- 
stances which  the  soil  has  lost. 

If,  in  the  formula, 


Phosphoric  acid. 


Potass. 
2-5 


Lime  and  magnesia. 
1-5 


Silicic  acid. 
3-0) 


we  determine  the  value  of  n,  which  is  meant  here  to 
designate  the  number  of  ^kilogrammes  of  phosphoric 


132  THE    SOIL. 

acid  which  the  four  crops  have  received  from  the  soil, 
we  find  for  the  wheat  crop  26  kilogrammes  of  phos- 
phoric acid,  for  the  potato  crop  25  kilogrammes,  for 
the  oat  crop  ^7  kilogrammes,  and  for  the  clover  crop 
36  kilogrammes — altogether,  114  kilogrammes  ;  multi- 
plying the  above  proportional  numbers  by  this  num- 
ber, we  obtain  the  sum  total  of  all  the  nutritive  sub- 
stances extracted  from  the  soil  by  the  four  crops. 

With  the  help  of  these  proportional  numbers,  we 
are  better  able  than  before  to  give  some  more  accurate 
explanations. 

Suppose  that  the  soil  of  a  certain  field  contains,  in 
an  available  state,  the  requisite  quantities  of  phosphoric 
acid,  potash,  lime,  and  magnesia,  to  supply  the  four 
crops  stated  above,  but  that  it  is  deficient  in  the  proper 
proportion  of  silicic  acid — containing,  for  example,  for 
1  part  by  weight  of  phosphoric  acid,  onj,y  2J  parts  of 
silicic  acid,  in  an  available  condition — this  deficiency 
will,  in  the  first  place,  be  felt  in  the  crops  of  cereal 
plants,  whilst  the  potato  and  clover  crops,  on  the  con- 
trary, will  not  be  at  all  diminished.  It  will  depend 
upon  the  weather  to  determine  whether  this  deficiency 
in  the  crop  of  cereal  plants  extends  both  to  corn  and 
straw  or  is  confined  to  the  straw  til  one.  A  want  of 
potash,  in  proportion  to  all  the  other  constituents,  will 
barely  affect  the  wheat  and  oat  crops,  but  it  will  reduce 
the  potato  crop ;  in  like  manner,  a  want  of  lime  and 
magnesia  will  impair  the  clover  crop. 

If  the  ground  can  furnish  one-tenth  more  potash, 
lime,  magnesia,  and  silicic  acid  than  corresponds  to  the 
given  proportion  of  phosphoric  acid — thus,  if, 

Phosphoric       prttao1l         Lime  and    c;^n-n  „  •<* 
acid.  Potash'        Magnesia.    Slllclc  acid' 

Instead  of 1  2'5  T5  3-0 

The  ground  should  be  able 

to  furnish 1  2'75  1-65  3-3 

the  crops  would  not  turn  out  larger  than  before.  But 
if,  in  such  a  field,  the  quantity  of  phosphoric  acid  is 
increased,  the  produce  will  increase,  until  the  right 
proportion  is  restored  between  the  phosphoric  acid  and 


EFFECT    OF   INCREASING   ONE   MINERAL    CONSTITUENT.    133 

the  other  mineral  constituents.  The  additional  supply 
of  phosphoric  acid  serves  in  this  case  to  increase  the 
amount  of  potash,  lime,  and  silicic  acid  in  the  produce  ; 
but  if  this  additional  supply  exceeds  one-tenth  of  the 
phosphoric  acid  present  in  the  soil,  the  quantity  in  ex- 
cess remains  ineffective.  Up  to  this  limit,  every  pound 
— nay,  every  ounce— of  phosphoric  acid  supplied  has, 
in  this  case,  a  fully  determinate  action. 

If  potash  or  lime  alone  is  wanted  to  restore  the 
right  proportion  among  the  nutritive  substances  in  the 
soil,  a  supply  of  ash  or  lime  will  increase  the  produce 
of  all  the  crops — the  additional  supply  of  lime  effecting, 
in  this  case,  an  increase  in  the  amount  of  phosphoric 
acid  and  potash  in  the  augmented  produce. 

If  we  find  that  a  soil  will  not  bear  a  remunerative 
crop  of  cereal  plants,  though  it  remains  fruitful  for 
other  plants,  such  as  potatoes,  clover,  or  turnips,  which 
require  just  as  much  phosphoric  acid,  potash,  and  lime, 
as  the  cereals,  we  may  assume  that  the  soil  had  the 
latter  substances  in  excess,  but  was  deficient  in  silicic 
acid.  And  if,  in  the  course  of  two  or  three  years,  dur- 
ing which  other  produce  is  cultivated  on  it,  the  land 
recovers  its  fertility  for  cereals,  this  must  be  because  it 
contained,  though  unequally  divided  and  distributed, 
an  excess  of  silicic  acid  also,  which,  during  the  fallow 
season,  migrated  from  the  places  where  it  was  in  excess 
to  those  where  it  was  deficient ;  so  that  when  the  sub- 
sequent period  of  cultivation  began,  there  was  in  all 
these  places  the  right  proportion  of  all  the  nutritive 
substances  needed  by  cereal  plants. 

For  similar  reasons,  if  peas  or  beans  can  be  culti- 
vated on  a  given  field  only  at  certain  intervals,  and  ex- 
perience shows  that  skilful,  industrious  tillage  is  usually 
more  effective  than  manure  in  shortening  these  inter- 
vals, we  may  infer  that  in  such  cases  the  nutritive  sub- 
stances were  not  deficient  in  total  quantity  in  the  whole 
field,  but  in  proper  proportion  in  all  parts  of  the  field. 


CHAPTEE    III. 

ACTION   OF   SOIL   ON   FOOD   OF   PLANTS   IN   MANURE. 

Manures  :  meaning  of  the  term  ;  their  action  as  food  of  plants  and  means  for  im- 
proving the  soil— Effect  on  soils  with  different  powers  of  absorption— Each  soil 
possesses  a  definite  power  of  absorption  ;  the  distribution  of  the  food  of  plants 
in  the  soil  is  inversely  to  the  power  of  absorption  ;  means  of  counteracting  the 
absorptive  power— Absorption  rumber,  notion  of;  comparison  of  in  different 
fields  ,  its  importance  in  husbandry— Soil  saturated  with  food  of  plants  ;  its 
comportment  with  water— Quantity  of  food  to  saturate  a  soil — A  saturated 
soil  not  required  for  the  growth  of  plants— Manuring  may  be  compared  to  the 
application  of  earth  saturated  with  food— Importance  of  the  uniform  distribu- 
tion of  food  in  manures  ;  fresh  and  rotted  stall  manure  ;  compost ;  importance 
of  powdered  turf  for  the  preparation  of  manure— Quantity  of  food  in  un- 
manured  fields  and  their  powers  of  production  ;  increase  of  the  latter  appa- 
rently out  of  proportion  to  the  manure  added ;  experiments  on  this  point ; 
explanation  ;  composition  of  the  soil  and  its  absorptive  power  compared  with 
the  requirements  of  the  plants  to  be  cultivated  on  it ;  surface  and  subsoil 
plants,  the  tillage  and  manurirg  respectively  required  by  each — Clover  sick- 
ness ;  experiments  of  Gilbert  and  Lawes  ;  their  conclusions  ;  value  of  them. 

THE  term  ' manure'  is  commonly  used  to  designate 
all  matters  which,  applied  to  a  field,  will  increase 
the  amount  of  its  future  produce,  or,  when  the  land  has 
been  exhausted  by  cultivation,  will  restore  its  capability 
of  yielding  remunerative  harvests. 

Manuring  agents  act  partly  in  a  direct  manner  as 
elements  of  food,  and  partly,  like  common  salt,  nitrate 
of  soda,  or  salts  of  ammonia,  by  enhancing  the  effect  of 
the  mechanical  operations  of  tillage,  so  that  they  fre- 
quently exert  as  favourable  an  influence  as  the  actual 
increase  of  the  nutritive  substances  in  the  ground. 

Of  the  two  last-named  compounds,  nitrate  of  soda 
contains  a  nutritive  substance  in  the  nitric  acid,  and 
salts  of  ammonia  in  the  ammonia.  Hence  it  is  ex- 
tremely difficult  in  individual  cases  to  determine 
whether  their  action  is  due  to  their  nutritive  constitu- 
ents, or  to  the  fact  that  they  have  brought  about  the 
absorption  of  other  nutritive  substances. 


ARABLE    SOILS    ABSORB   MINERAL   MATTERS.  135 

In  a  fertile  soil  tillage  and  manuring  have  a  definite 
relation  to  one  another.  If,  after  a  rich  harvest,  the 
field  is  prepared  by  tillage  alone  to  produce  a  similar 
rich  crop  in  the  next  year,  that  is,  if  the  mechanical 
means  are  sufficient  to  distribute  the  store  of  nutritive 
substances  so  uniformly  that  the  plants  of  the  following 
season  will  find  as  much  nutriment  in  all  parts  of  the 
soil  as  during  the  last,  any  further  supply  of  mineral 
constituents  by  manuring  would  be  mere  waste ;  but, 
where  a  field  is  not  in  that  condition,  the  deficiency 
must  be  supplied  by  manure,  in  order  to  restore  the 
original  power  of  production.  Thus,  in  a  certain  sense, 
the  mechanical  operations  of  tillage  and  of  manure  are 
supplementary  to  one  another. 

Of  two  similar  fields,  manured  in  exactly  the  same 
way,  if  the  one  has  been  well  tilled,  and  the  other  bad- 
ly tilled,  the  former  will  yield  a  richer  crop,  i.  e.  the 
manure  seems  to  have  a  better  effect  upon  this  than 
upon  the  badly  tilled  field. 

If  one  of  two  farmers  knows  his  land  better,  and 
cultivates  it  more  judiciously  than  the  other,  the  former 
will,  in  a  given  time,  obtain  as  good  crops  with  less 
manure,  or  richer  crops  with  the  same  quantity  of 
manure. 

All  these  facts  should  be  considered  in  estimating 
the  value  of  manuring  agents;  but,  as  science  has  no 
standard  for  measuring  the  results  of  the  mechanical 
operations  of  tillage,  this  cannot  be  taken  into  account 
here,  and  we  must  confine  ourselves  to  that  which  can 
be  scientifically  measured  and  compared. 

When  two  fields  are  equally  rich  in  nutritive  sub- 
stances', it  often  happens  that  the  one,  by  tillage  alone, 
or  by  tillage  combined  with  manuring,  will  be  ""brought 
much  sooner  than  the  other  into  a  condition  to  yield  a 
succession  of  remunerative  crops  of  cereal  or  other 
plants. 

On  a  light  sandy  soil,  all  kinds  of  manure  act  more 
rapidly  and  effectively  than  on  clay.  The  sand  is  more 
grateful,  say  the  farmers,  for  the  manure  bestowed 
upon  it,  and  yields  a  more  abundant  return  than  other 


136      ACTION   OF   SOIL   ON   FOOD   OF   PLANTS    IN   MANURE. 

soils  for  what  it  has  received.  The  nitrogenous 
manures,  such  as  wool,  horn-shavings,  "bristles,  and 
blood,  which,  as  we  know  for  a  certainty,  act  by  the 
formation  of  ammonia,  frequently  exercise  a  far  more 
favorable  influence  upon  many  plants  than  ammonia 
itself.  In  other  cases,  bone-earth  acts  more  powerfully 
upon  the  future  crop  than  superphosphate  of  lime ;  and 
sometimes  ash  will  prove  more  fertilising  than  if  the 
amount  of  potash  contained  in  it  were  directly  laid 
upon  the  field. 

All  these  facts  are  most  intimately  connected  with 
the  faculty  of  arable  soils  to  extract  or  absorb  phos- 
phoric acid,  ammonia,  potash,  and  silicic  acid  from 
their  solutions.  The  restoration  of  the  productive 
power  to  an  exhausted  field  by  the  mechanical  opera- 
tions of  tillage  and  fallowing  alone,  without  manure, 
presupposes  that  in  certain  parts  of  the  field  there  must 
have  been  an  excess  of  nutritive  substances  which  dis- 
persed in  the  soil  and  extended  to  other  places  where 
such  substances  were  deficient. 

This  distribution  demands  a  certain  time.  The 
excess  of  nutritive  elements  must  first  be  dissolved,  that 
they  may  be  able  to  move  towards  those  parts  which 
have  lost  their  elements  of  food  by  a  previous  harvest. 
The  closer  these  superabundant  deposits  lie  to  each 
other,  the  shorter  is  the  way  over  which  the  substances 
have  to  travel ;  and  the  less  the  absorptive  power  of 
the  intervening  earth  particles  for  these  nutritive  sub- 
stances, the  more  speedily  will  the  productive  power 
of  the  soil  be  restored. 

Every  arable  soil  possesses,  for  potash  and  the  other 
substances  mentioned,  a  determinate  power  of  absorp- 
tion, which  may  be  expressed  by  the  number  of  milli- 
grammes absorbed  by  1  cubic  decimetre  (  =  1000  cubic 
centimetres)  of  earth.  Thus,  for  instance  : — 

Cubic    Cubic 
decimet.  inches.  Milligrammes.  Grains. 

1  =  61  of  lime  soil         from  Cuba                absorbed  1360  =  21  potash. 

1        "  loam                   "      Bogenhausen          "         2260  =  35      " 

1        "  soil                     "      Weihenstephan      "         2601  =  40      " 

1       "  soil                    "     Hungary                "        3377  =  52      " 

1       "  garden  mould    "     Munich                   "         2344  =  36      " 


ABSORPTIVE   POWER   OF   SOIL   FOR   SILICIC   ACID.       137 

It  will  be  seen  at  once  that  these  differences  in 
absorptive  power  are  very  considerable.  One  volume 
of  earth  from  Weihenstephan  absorbs  nearly  twice  as 
much  potash  as  an  equal  bulk  of  soil  from  Cuba ;  the 
Hungarian  earth,  here  examined,  absorbs  2-J  times  as 
much. 

These  figures  show  that  a  certain  quantity  of  pot- 
ash, say  2600  milligrammes,  if  supplied  to  the'Weihen- 
stephan  soil,  will  spread  in  a  space  of  1  cubic  decimetre 
of  earth.  If  we  were  to  pour  the  potash,  in  solution, 
on  a  small  plot  of  ground,  1  square  decimetre  in  area, 
the  potash  would  penetrate  to  a  depth  of  1  decimetre 
(=  3'94  inches),  and  no  deeper  ;  every  cubic  centimetre 
(—  -061  cubic  inch)  would  receive  2*6  milligrammes 
(—  -04  grain)  of  potash,  but  the  layers  beneath  would 
receive  none,  or  at  least  no  appreciable  quantity  of  it. 

If  the  same  solution  were  poured  on  an  equal  area 
of  Hungarian  or  Cuban  soil,  the  potash  filtering 
through  would  penetrate,  in  the  former,  to  a  depth  of 
somewhat  above  7  centimetres  (=  2'7  inches) ;  in  the 
latter,  to  a  depth  of  19  centimetres  (=  7*5  inches). 

The  diffusibility  of  potash  in  a  soil  is  in  an  inverse 
ratio  to  the  absorptive  power  of  that  soil ;  half  the 
absorptive  power  corresponds  to  double  the  diffusibility. 
In  a  similar  way  potash  will  spread  in  a  field  during 
the  time  of  fallow.  From  the  spot  where  the  potash  is 
set  free  from  a  silicate  by  disintegration,  it  will  diffuse 
itself  through  a  volume  of  earth  so  much  the  larger  in 
proportion  as  the  absorptive  power  of  the  earth  for 
potash  is  smaller. 

The  absorptive  power  of  arable  soil  for  silicic  acid 
differs  just  as  much  as  for  potash. 

Thus  from  a  solution  of  silicate  of  potash,  1  cubic 
decimetre  (=61  cubic  inches)  of  these  different  soils 
absorbed  the  following  quantities  of  silicic  acid  : — 

Forest  soil.         Hungarian.     Garden  mould  I.  Bogenhausen.  Garden  mould  II. 
Milligr.  Grains.   Milligr.  Grains.  Milligr.  Grains.  Milligr.  Grains.  .Milligr.  Grains. 
15=0'23        2644=43-8        2425=37'3        2007=31        1085=16-7 

Whence  to  express  the  relative  diffusibility  of  silicic 


138      ACTION    OF   SOIL   ON   FOOD   OF   PLANTS    IN   MANURE. 

acid   in    these   soils,  we  have   the  following  propor- 
tion : — 

Hungarian.      Garden  mould  I.     Bogenhausen.     Garden  mould  II.      Forest  soil. 
1-0  1'09  1-31  2-43  17-6 

The  same  quantity  of  silicic  acid  which  would  satu- 
rate 1000  cubic  centimetres  of  Hungarian  earth,  would 
furnish  a  maximum  supply  for  1311  cubic  centimetres 
of  Bogenhausen  loam,  2430  cubic  centimetres  of  gar- 
den mould  II.,  and  17,600  cubic  centimetres  of  forest 
soil. 

Ammonia,  in  the  pure  state,  or  in  the  form  of  salts 
of  ammonia,  is  absorbed  by  arable  soil  just  in  the  same 
way  as  potash  :  one  kilogramme  (=  2'2  Ibs.)  of  the  fol- 
lowing earths  will  absorb  respectively  these  quantities 
of  ammonia : — 

Cuban.  Schleissheim.  Garden  mould.  Bogenhausen. 

Milligr.  Grains.         Milligr.  Grains.  Milligr.  Grains.  Milligr.  Grains. 

6520=85  3900=60  3240=49*9  2600=40 

which   gives  the  following   numbers  for  the  relative 
diffusibility  of  ammonia  : — 

Cuban.  Schleissheim.  Garden  mould.  Bogenhausen. 

1-0  1-24  1-50  2.12 

The  absorptive  power  of  arable  soils  for  phosphate 
of  lime,  phosphate  of  magnesia,  and  phosphate  of  mag- 
nesia and  ammonia,  may  be  determined  in  the  same 
way,  and  the  relative  diffusibility  of  these  several  con- 
stituents in  different  soils  may  be  expressed  numerically. 

By  the  term  '  absorption  number,'  we  designate,  in 
the  following  pages,  the  quantity  reckoned  in  milli- 
grammes (—  0-0154:  grain)  of  the  several  mineral  con- 
stituents, which  one  cubic  decimetre  (=61  cubic  in- 
ches) of  earth  extracts  from  their  solutions. 

To  determine  the  condition  of  a  field,  the  action  of 
the  manures  applied  to  it,  and  the  depth  to  which  the 
several  nutritive  substances  will  penetrate,  it  is  import- 
ant to  establish  proportionately  the  absorptive  power 
of  the  soil  for  each  of  them ;  thus,  for  example,  1  cubic 
decimetre  of  Bogenhausen  loam  absorbs :— 


riSPEKSION   OF   PHOSPHATE    OF    LIME   IN    SOIL.        139 


Ammonia. 

Phosphate  of 
Magnesia  and 
Ammonia. 

Potash. 

Phosphate 
of 
Lime. 

Milligrammes. 
2600 

Milligrammes. 
2565 

Milligrammes. 
2366 

Milligrammes. 
1098 

Relative  diffusibility 

1-0 

1-01 

1-10 

2-36 

Accordingly,  the  second  series  of  these  numbers 
expresses  that  if  a  certain  quantity  of  ammonia  in  its 
passage  through  the  soil  penetrates  to  a  depth  of  10 
centimetres,  the  same  quantity  of  potash  will  attain  a 
depth  of  11  centimetres,  and  a  like  quantity  of  phosphate 
of  lime  will  reach  23*6  centimetres. 

In  a  soil  like  the  Bogenhausen,  which  absorbs  per 
cubic  decimetre  1098  milligrammes  of  dissolved  phos- 
phate of  lime,  let  us  suppose  that  granules  of  phosphate 
of  lime  are  dispersed,  and  that  in  one  spot  of  the 
ground  one  of  these  granules  weighing  22  milligrammes 
(J-  of  a  grain)  during  the  course  of  a  certain  time  be- 
comes soluble  in  carbonic  acid  water,  and  spreads  in- 
the  surrounding  soil ;  first  of  all  the  earth  immediately 
around  this  granule  will  be  saturated  with  phosphate 
of  lime,  then  as  the  carbonic  acid  remains  in  the  water 
and  its  solvent  power  continues,  a  fresh  solution  will 
be  formed,  which  will  again  offer  phosphate  of  lime  for 
absorption  to  a  wider  extent  of  earth ;  at  length,  when 
the  22  milligrammes  of  phosphate  of  lime  are  thorough- 
ly diffused  in  the  surrounding  earth,  they  will  supply 
20  cubic  decimetres  of  earth  with  the  maximum  of  this 
nutritive  substance  in  the  form  best  suited  for  absorp- 
tion. The  rapidity  with  which  the  phosphate  of  lime 
will  dissolve  and  spread  depends  upon  its  extent  of  sur- 
face ;  accordingly,  if  we  suppose  the  granule  to  be 
converted  into  a  fine  powder,  a  solution  will  be  formed 
richer  in  phosphate  of  lime  just  in  proportion  to  the 
greater  number  of  particles  exposed  within  the  same 
time  to  the  solvent  action  of  the  carbonic  acid.  There- 
fore, assuming  that  in  a  certain  state  of  greater  division 
twice  or  three  times  as  much  is  dissolved  in  a  given 


140     ACTION    OF    SOIL    ON   FOOD    OF   PLANTS    IN   MANURE. 

time,  we  infer  that  distribution  under  favourable  cir- 
cumstances will  take  place  in  one-half  or  one-third  of 
the  time  it  would  take  without  the  division. 

If,  therefore,  in  a  given  case  the  restoration  of  the 
productive  power  in  a  soil  by  fallowing  or  manuring 
depends  upon  the  earth  when  drained  of  phosphoric 
acid  by  the  roots  of  plants  receiving  the  needful  phos- 
phoric acid  back  again  from  the  surrounding  earthy 
particles,  it  follows  that  with  an  equal  amount  of  earthy 
phosphates  the  time  required  to  accomplish  this  end 
will  be  shortened  in  proportion  to  the  division  of  the 
earthy  phosphates. 

Straw  manure,  after  decay,  leaves  silicate  of  potash 
behind,  and  in  the  process  of  putrefaction  evolves  car- 
bonic acid,  which  by  its  action  upon  the  silicates  sets 
free  silicic  acid  ;  hence  by  using  this  manure  the  diffu- 
sion of  silicic  acid  must  be  promoted  as  the  organic 
matters  absorb  none  of  it,  and  they,  when  mixed  with 
the  earth,  must  diminish  the  absorptive  powers  of  the 
soil. 

The  forest  soil  above  mentioned  absorbed  only  very 
small  quantities  of  silicic  acid  from  its  alkaline  solu- 
tions ;  and  it  is  evident  that  the  addition  of  such  soil  to 
the  Hungarian  earth  would  have  the  effect  of  diffusing 
through  a  larger  volume  of  earth  the  silicic  acid  set  free 
by  disintegration. 

It  is  not,  however,  the  case  with  every  soil,  that  its 
absorptive  power  for  silicic  acid  decreases  in  equal  pro- 
portion to  the  quantity  of  combustible  substances 
which  it  contains.  Thus  the  Hungarian  earth  above 
alluded  to  contains  more  (9*8  per  cent.)  combustible 
matter  than  the  Bogenhausen  loam  (8*7  per  cent.),  yet 
its  absorptive  power  for  silicic  acid  is  not  less  but 
greater  than  that  of  the  latter.  Hence  it  follows  that 
there  are  other  circumstances  which  influence  the 
absorptive  power  of  the  soil,  and  consequently  the 
diffusibility  of  silicic  acid.  A  soil  abounding  in  hy- 
drated  silicic  acid  will,  under  any  circumstances,  absorb 
less  silicic  acid  than  one  deficient  in  that  acid,  even 


FOOD  OF  PLANTS  IN  SANDY  SOILS  AND  LOAMS.   141 

though  the  latter  soil  should  contain  a  much  larger 
amount  of  organic  substances. 

The  '  absorption  numbers '  of  two  different  arable 
soils  afford  no  criterion  for  determining  the  quality  of 
the  soil  or  the  amount  of  nutritive  substances  which  it 
contains ;  they  merely  tell  us  that,  in  the  one  soil,  the 
elements  of  the  food  of  plants  will  spread  beyond  cer- 
tain places,  further  than  in  the  other  ;  that  the  one  soil 
opposes  greater  obstacles  to  their  diffusion  than  the 
other.  The  farmer,  in  learning  the  strength  of  these 
obstacles,  finds  out  by  experience  whether  they  exert  a 
beneficial  or  adverse  influence  upon  the  cultivation  of 
his  fields,  and  ascertains  the  means  of  removing  the 
injurious  or  strengthening  the  beneficial  influences. 

On  comparing  a  fruitful  sandy  soil  with  an  equally 
fruitful  loam  or  marl,  as  regards  the  nutritive  sub- 
stances contained  in  them,  we  are  surprised  to  find  that 
the  sand  with  one-half  or  even  one-fourth,  of  the  total 
substances  contained  in  the  loam,  will  furnish  an 
equally  rich  harvest.  To  understand  this  circumstance 
properly,  we  must  remember  that  the  nutrition  of  a 
plant  depends  less  upon  the  quantity,  than  upon  the 
form  of  the  nutriment  in  the  soil ;  just  in  the  .same 
way  as,  for  example,  half  an  ounce  of  animal  charcoal 
presents  as  large  an  acting  surface  as  a  pound  of  wood 
charcoal.  If  the  smaller  quantity  of  nutritive  sub- 
stances in  the  sandy  soil  presents  as  large  a  surface  for 
absorption  as  the  larger  quantity  of  those  substances  in 
the  loam,  the  plants  must  thrive  as  well  upon  the 
former  as  upon  the  latter. 

If  a  cubic  decimetre  of  a  fruitful  loam  is  mixed 
with  9  cubic  decimetres  of  silicious  sand,  so  that  every 
particle  of  sand  is  surrounded  with  particles  of  loam, 
as  many  root-fibres  and  particles  of  loam  will  come 
into  contact  in  the  mixed  as  in  an  equal  volume  of  the 
unmixed  soil ;  and  if  all  the  particles  of  loam  can  yield 
the  same  nutriment,  plants  will  receive  from  the  mixed 
just  as  much  as  from  the  unmixed  soil,  though,  on  the 
whole,  the  latter  is  ten  times  richer. 

All  fruitful  sandy  soils  consist  of  a  mixture  of  sand 


ACTION   OF   SOIL   ON   FOOD   OF   PLANTS   IN   MANURE. 

with  more  or  less  clay  or  loam ;  and  as  silicious  sand 
has  a  very  limited  power  of  absorbing  potash  and  the 
other  mineral  constituents  of  plants,  the  ingredients  of 
the  supplied  manure,  which  have  become  soluble, 
spread  sooner  and  penetrate  deeper  into  a  sandy  soil, 
which  also  gives  back  comparatively  more  of  them  than 
any  other  soil.  In  many  cases,  therefore,  a  stiff  loam 
may  be  improved  by  sand ;  as,  on  the  other  hand,  the 
addition  of  loam  to  a  sandy  soil  will  cause  the  nutritive 
substances,  supplied  by  the  manure,  to  remain  nearer 
the  surface  or  to  be  retained  more  firmly  in  the  arable 
top  layer. 

But  as  a  sandy  soil  gives  up  at  harvest  more  nutri- 
tive substances  in  proportion  to  what  it  contains,  than 
a  fruitful  loam,  a  more  speedy  exhaustion  is  the  conse- 
quence ;  its  power  of  production  does  not  last  long, 
and  can  only  be  sustained  by  frequent  manuring,  to 
supply  the  constituents  which  have  been  removed. 
Exactly  in  the  same  degree,  as  the  manure  acts  more 
beneficially  in  restoring  the  productive  power,  the 
effect  of  the  mechanical  operations  of  tillage  becomes 
less  marked. 

The  same  causes  which  restore  to  an  exhausted  loam 
a  large  portion  of  its  lost  productive  power,  if  the  land 
is  but  sufficiently  broken  up  by  the  plough,  are  at  work 
in  a  sandy  soil  also ;  but  they  produce  little  or  no  re- 
sult, because  the  sand  is  deficient  in  those  substances 
which  the  action  of  the  plough  is  intended  to  render 
available. 

As  the  surface  of  a  hectare  (2-J  acres)  represents  1 
million  square  decimetres,  the  absorption  numbers  ex- 
press the  number  of  kilogrammes  of  potash,  phosphoric 
acid,  and  silicic  acid,  which,  when  applied  on  a  field, 
will  spread  from  the  surface  downwards  to  a  depth  of 
10  centimetres  (about  4  inches).  Yolker,  Henneberg, 
and  Stohmann,  in  experiments  made  upon  different 
soils  to  determine  their  absorption  numbers  for  am- 
monia, observed  that  the  earth  retained  a  greater 
quantity  from  a  concentrated  than  from  a  dilute  solu- 
tion of  ammonia  or  salts  of  ammonia ;  whence  it  fol- 


ABSORPTION   OF   AMMONIA   BY    SOIL.  143 

lows,  as  a  matter  of  course,  that  the  ammonia  is  divided 
between  the  water  and  the  soil,  and  that  from  a  soil 
fully  saturated  with  ammonia,  pure  water  will  extract 
a  certain  quantity  of  it ;  just  as  charcoal  will  complete- 
ly withdraw  the  colouring  matter  from  a  slightly 
coloured  fluid,  but  from  one  more  deeply  coloured  will 
extract  a  much  larger  quantity  ;  a  part  of  which,  how- 
ever, is  but  feebly  combined  and  may  be  removed  by 
water. 

In  Yolker's  experiments,  treatment  with  a  copious 
amount  of  water  extracted  one-half  the  ammonia  from 
a  soil  saturated  therewith  ;  the  other  half  was  retained 
by  the  earth. 

Soils  which  contain  much  decaying  vegetable  mat- 
ter absorb  more  ammonia  and  retain  it  more  firmly 
than  soils  that  are  poorer  in  decaying  organic  substan- 
ces. Even  assuming  that  two  cubic  decimetres  of 
earth,  instead  of  one,  are  required  to  retain  completely 
the  amount  of  ammonia  indicated  by  the  absorption 
number,  it  is  clear  that  ordinary  manuring  with  an 
agent  abounding  in  ammonia,  such  as  guano  or  salts  of 
ammonia,  can  enrich  the  earth  with  this  substance  only 
to  a  very  inconsiderable  depth. 

To  saturate  with  ammonia,  a  hectare  (2-J-  acres)  of 
Bogenhausen  loam,  from  the  surface  downwards  to  the 
depth  of  one  decimetre,  fully,  or  to  half-saturate  it  to 
the  depth  of  two  decimetres  (7*8  inches),  would  require 
a  supply  of  2600  kilogrammes  or  52  cwts.  of  pure  am- 
monia, or  200  cwts.  of  sulphate  of  ammonia. 

If  800  kilogrammes  of  guano,  containing  10  per 
cent,  of  ammonia,  are  applied  to  a  hectare  of  Bogen- 
hausen soil,  the  amount  of  ammonia  added  is  80  kilo- 
grammes (=  176  Ibs.),  which  is  a  little  more  than  the 
thirtieth  part  of  the  quantity  required  to  half-saturate 
the  soil  to  a  depth  of  20  centimetres.  "Without  the 
plough  and  harrow,  the  quantity  of  ammonia  contained 
in  the  guano  would  not  penetrate,  at  the  furthest, 
deeper  than  7  millimetres  (=  0*27  inch).  But  to  thrive 
well,  plants  do  not  require  a  soil  saturated  with  nutri- 
tive substances ;  for,  the  absorption  numbers  we  have 


144     ACTION   OF   SOIL   ON   FOOD   OF  PLANTS   IN  MANURE. 

quoted  sufficiently  show  how  far  the  arable  soils  are 
from  a  state  of  complete  saturation.  All  that  plants 
need  for  their  proper  nutrition  is  that  their  roots,  down- 
wards in  the  soil,  should  come  in  contact  with  a  certain 
quantity  of  saturated  earth  ;  and  the  mechanical  opera- 
tions of  tillage  have  the  important  object  of  conveying 
earthy  particles  saturated  with  nutritive  substance,  and 
of  mixing  them  with  others,  which  by  preceding  culti- 
vation have  become  poorer  in  those  constituents. 

The  average  crop  from  a  hectare  of  wheat  (2000  kilo- 
grammes —  4400  Ibs.  of  grain,  and  5000  kilogrammes 
=  11,000  Ibs.  of  straw)  contains  52  million  milli- 
grammes =  114*4  Ibs.)  of  potash,  26  million  milli- 
grammes (=  57'2  Ibs.)  of  phosphoric  acid,  and  54  mil- 
lion milligrammes  (=  118-8  Ibs.)  of  nitrogen.  As- 
suming the  nitrogen  to  be  supplied  by  the  soil,  the 
wheat  plants  growing  on  a  square  metre  (=  10-75 
square  feet)  receive  the  ten-thousandth  part  of  the  pot- 
ash, phosphoric  acid,  and  nitrogen,  or  altogether  13,200 
milligrammes  (=  203'3  grains).  Supposing  100  plants 
to  grow  upon  a  square  metre,  each  of  these  takes  up 
from  the  soil  Io2  milligrammes  of  these  constituents,  or 
54  milligrammes  of  nitrogen  —  65  milligrammes  or  1 
grain  of  ammonia,  52  milligrammes  (=  0-8  grain)  of 
potash,  and  26  milligrammes  (=  0'4  grain)  of  phos- 
phoric acid. 

Each  cubic  centimetre  (=  '06  cubic  inch)  of  Bogen- 
hausen  loam  absorbs  to  saturation  2'6  milligrammes 
(=•04  grain)  of  ammonia,  2'3  milligrammes  (=  0-35 
grain)  of  potash,  and  0-5  milligrammes  (=  '008  grain) 
of  phosphoric  acid ;  therefore,  to  restore  a  sufficiency 
of  these  constituents  which  the  wheat  plant  has  taken 
from  the  soil,  would  require  a  supply  of  25  cubic  cen- 
timetres of  the  saturated  earth,  and  25  milligrammes 
of  phosphate  of  lime  for  each  square  decimetre  of  the 
field.  Calculated  upon  a  square  decimetre  (  =  15|- 
square  inches)  of  surface  and  a  depth  of  20  centimetres 
(  =7'8  inches),  these  25  cubic  centimetres  constitute  the 
eightieth  part  of  the  entire  mass  of  earth. 

The  experiments  of  ISfageli  and  Zoeller,  before  de^ 


EAETH  SATURATED  WITH  MINERAL  MATTER.    145 

scribed,  furnish  a  good  example  of  this  kind  of  manur- 
ing. The  manure  consisted  of  turf,  partly  saturated 
with  nutritive  substances  and  mixed  with  three  volumes 
of  turf  almost  absolutely  unfruitful ;  this  constituted  a 
soil  of  the  same  degree  of  fertility  as  good  garden 
mould. 

Such  an  addition  of  earth  saturated  with  mineral 
constituents  does  not  usually^take  place ;  but  the  ordi- 
nary method  of  manuring  comes  exactly  to  the  same 
result.  The  field  is  dressed  with  liquid  or  solid  manur- 
ing matters  containing  nutritive  substances,  which  com- 
bine immediately  if  in  solution,  gradually  if  requiring  a 
certain  time  for  solution,  with  the  earthy  particles  with 
which  they  are  in  contact,  and  saturate  them  ;  and  it  is 
properly  this  earth,  saturated  with  manuring  matters 
on  its  outermost  surface  or  in  the  inner  parts  with  which 
the  farmer  manures,  i.  e.  with  which  he  replaces  the 
mineral  constituents  withdrawn  from  the  soil. 

Experience  has  taught  the  agriculturist  which  parts 
of  the  soil  may  be  enriched  with  nutritive  substances 
most  profitably  for  himself,  or  rather  for  his  plants ; 
and  it  is  remarkable  in  the  highest  degree  how  he  has 
found  out  the  proper  method  of  manuring  in  accordance 
with  the  nature  of  the  intended  crop,  the  soil,  and  the 
period  in  which  the  plants  are  developed  ;  also  whether 
to  proceed  by  simple  top-dressing  or  by  ploughing  the 
manure  in  to  a  greater  or  less  depth.* 

In  these  respects  the  successes  of  the  agriculturist 
would  be  still  greater  if  the  nutritive  substances  con- 
tained in  the  manure  principally  used,  namely,  farm- 
yard manure,  were  more  uniformly  mixed  and  distrib- 
uted, because  this  would  lead  to  a  more  uniform  distri- 
bution of  them  in  the  soil. 

Farm-yard  manure  is  a  very  irregular  mixture  of 
decaying  straw  and  vegetable  remains,  combined  with 
solid  animal  excrements,  the  latter  constituting  the 
smaller  portion  of  the  whole  mass :  it  is  soaked  with 
fluids  which  hold  ammonia  and  potash  in  solution.  If 
a  hundred  samples  be  taken  from  a  hundred  different 

*  '  Journ.  of  the  Royal  Agric.  Soc.  England,'  t.  21,  p.  330. 

7 


146      ACTION    OF   SOIL   ON   FOOD    OF   PLANTS    IN   MANURE. 

parts  of  a  dung-heap,  the  analysis  of  each  sample  will 
show  different  proportions  of  nutritive  constituents : 
hence  it  is  evident  that  by  a  dressing  with  i arm-yard 
manure  hardly  two  spots  in  the  soil  will  receive  the 
same  amount  of  nutritive  substances. 

The  spot  occupied  by  a  dung-heap  on  a  field  during 
rainy  weather,  will  be  marked  in  the  whole  period  of 
vegetation,  and  often  even  in  the  second  year  by  a  more 
luxuriant  growth  of  plants,  especially  of  cereals,  though 
the  plants  growing  on  it  will  not  always  furnish  a  per- 
ceptibly greater  yield  of  grain.  If  the  potash  and  am- 
monia received  by  this  spot  above  what  was  required 
for  the  formation  of  grain,  had  been  more  evenly 
distributed,  and  thus  accessible  to  the  plants  in  other 
places,  the  yield  of  corn  from  those  plants  would  have 
been  increased  ;  whereas  the  excessive  accumulation  in 
one  place  merely  increased  the  yield  of  straw.  The 
unequal  distribution  of  the  other  ingredients  of  farm- 
yard manure  in  the  soil  leads  to  a  similar  inequality  in 
the  developement  of  the  several  parts  of  the  cereal 
plants.  On  an  ideal  field,  with  the  nutritive  substances 
supposed  to  be  distributed  with  perfect  uniformity,  and 
all  accessible  to  the  roots,  all  the  cereal  plants,  other 
conditions  being  the  same,  should  attain  the  same 
height,  and  each  ear  yield  the  same  number  and  weight 
of  grains. 

In  the  short,  rotten  farm-yard  manure,  the  nutritive 
substances  are  much  more  uniformly  distributed  than 
in  the  fresh  straw  manure  ;  and  the  agriculturist  effects 
a  still  more  uniform  diffusion  by  mixing  the  dung  with 
earth,  and  turning  it  into  so-called  compost.  As  dung 
and  all  other  manuring  agents  act  only  through  the 
medium  of  the  earthy^  particles  that  have  become  sat- 
urated with  the  nutritive  substances  contained  in  the 
manure,  it  is,  under  certain  -circumstances,  advanta- 
geous for  the  farmer  to  prepare  a  saturated  earth,  by 
help  of  his  farm-yard  manure,  and  to  use  this  composi- 
tion, which  may  of  course  be  made  on  the  field  itself. 
If,  in  accordance  with  Yoelker's  valuable  experiments, 
we  assume  one  cubic  metre  (  =  35  cubic  feet)  of  farm- 


USE   OF  EARTH   SATURATED   WITH  MANURE.  147 

yard  manure  (500  kilogrammes  or  1000  pounds)  to  con- 
tain 660  pounds  of  water,  6  pounds  of  potash,  and  12 
pounds  of  ammonia ;  and  if  this  were  mixed  with  1 
cubic  metre  of  earth,  of  which  1  cubic  decimetre  (  =  61 
cubic  inches)  absorbs  3000  milligrammes  (  =  46 '2  grs.) 
of  potash,  and  6000  milligrammes  (  =  92*4  grs.)  of  am- 
monia ;  then,  after  the  complete  decay  of  organic  matter 
in  the  manure  (about  25  per  cent,  of  its  weight),  and 
the  evaporation  of  one-half  of  the  water,  the  result 
would  be  1J  cubic  metre  of  earth  fully  saturated  with 
all  the  nutritive  substances  in  the  manure.  Soils  that 
will  absorb  the  stated  amount  of  potash  and  ammonia 
are  everywhere  to  be  found,  and  the  farmer  will  have 
no  difficulty  in  choosing  the  earth  most  suitable  for  his 
compost  heaps. 

It  is  well  known  that  dung  exercises  a  mechanical 
action  also,  tending  to  diminish  the  cohesion  of  a  com- 
pact soil,  or  to  make  a  heavy  soil  lighter  and  more 
porous.  For  soils  of  this  kind  composts  are  not  so  well 
suited  ;  and,  instead  of  the  earth,  some  very  loose  body 
ought  to  be  substituted  for  mixing  with  the  manure. 
Turf-dust  will  be  found  to  answer  the  purpose  best.* 

If  the  crops  obtained  from  many  fields  by  manuring 
with  farm-yard  manure,  bone-earth,  guano,  and  in  many 
cases  also  with  wood-ashes  and  lime,  are  compared  with 
what  the  same  fields  will  yield  in  the  unmanured  state, 
the  effect  of  these  manures  seems  truly  marvellous. 

The  yield  of  an  unmanured  field  must  correspond 

*  It  is,  perhaps,  much  more  important  than  manuring  with  composts, 
which  always  involves  much  labour  and  more  carriage,  to  take  advantage 
of  the  absorbent  properties  of  earth  and  turf,  for  fixing  the  nutritive  sub- 
stances contained  in  liquid  manure.  By  covering  the  ground  of  a  dung- 
hill, on  an  area  of  10  metres  square  (=10'5  sq.  feet)  with  a  layer  of  loose 
turf,  1  metre  (=  3*3  feet)  deep,  a  bed  of  100  cubic  metres  (=  3,500  cubic 
feet)  of  turf  is  formed,  into  which  the  liquid  portion  of  the  manure  in  the 
dunghill  may  safely  be  allowed  to  soak  without  the  least  risk  of  losing  the 
smallest  portion  of  its  useful  ingredients.  The  turf  may  then  be  used,  like 
dung,  for  manuring,  and  of  course  must  be  renewed  every  year.  On  fields 
which  are  not  tilled,  such  as  meadows,  liquid  manure  will  naturally  act 
with  greater  rapidity.  The  turf  found  in  the  neighbourhood  of  Munich, 
when  reduced  to  powder,  absorbs  7'892  grammes  (=122  grains)  of  potash, 
and  4' 169  grammes  (=64  grains)  of  oxide  of  ammonium,  per  1000  cubic 
centimetres  (=61  cubic  inches)  weighing  330  grammes  (1I|  ozs.). 


148     ACTION   OF   SOIL   ON   FOOD   OF   PLANTS   IN   MANURE. 


with  the  available  nutritive  substances  which  it  contains ; 
a  lower  crop  corresponds  to  a  smaller  store  of  these  mat- 
ters. In  any  one  of  the  cases  stated,  if  we  compare  the 
amount  of  nutritive  substances  in  the  unmanured  por- 
tion of  a  field  with  the  crop  which  it  produces,  and  then 
compare  the  additional  nutritive  substances  or  the 
quantity  of  dung  with  the  increased  crop,  the  increase 
appears  to  be  beyond  all  proportion  much  greater  than 
the  additional  supply.  Hence  we  are  led  to  suppose 
that  the  phosphoric  acid,  potash,  and  ammonia  given 
in  the  manure  must  be  much  more  efficacious  than  the 
substances  present  in  the  soil,  or  that  the  greater  por- 
tion of  them  in  the  soil  was  ineffective,  and  that  its 
power  of  production  had  depended  chiefly  upon  the 
supply  of  manure.  Thus  it  arises,  that  while  some 
farmers  believe  that  all  manure  can  be  dispensed  with 
because  tillage  is  enough  to  render  a  field  productive, 
others  suppose  that  the  field  can  be  kept  fruitful  only 
by  manuring.  All  these  views  are  based  upon  indi- 
vidual cases  and  have  no  general  application ;  for 
neither  one  nor  the  other  of  the  contending  parties 
have  any  clear  knowledge  of  the  true  causes  upon 
which  the  power  of  production  of  this  kind  is  founded. 
In  the  experiments  made  in  the  year  1857,  by  order 
of  the  General  Committee  of  the  Bavarian  Agricultural 
Union,  on  the  action  of  phosphorite  upon  certain  fields 
at  Schleissheim  deficient  in  phosphoric  acid,  the  follow- 
ing crops  of  summer  wheat  were  reaped  from  two  plots 
of  ground,  one  unmanured  the  other  dressed,  per  hec- 
tare (  =  2J  acres),  with  241 '4  kilogrammes  (  =  530 
Ibs.)  of  phosphoric  acid,  657*4  kilogrammes  (  =  13  cwt.) 
of  phosphorite  decomposed  by  sulphuric  acid  : — 


1857. 

J. 

Total  crop. 

Corn. 

Straw. 

Manured    with     657 
kilogrms.  of  phos- 
phate of  lime  .... 
TJumanured 

Kilogr.     Cwt. 

5114-7  =  105-0 
2301-0—  45-0 

Kilogr.     Cwt. 

1301-7=25-5 
644-3—12-5 

Kilogr.     Cwt. 

3813-0=75-0 
1656-7—32-5 

KATIO   OF   CROP   TO   PHOSPHORIC    ACID   IN    SOIL.       149 

From  a  chemical  analysis  made  by  Dr.  Zoeller,  of 
the  Munich  Laboratory,  the  soil  of  this  field  was  found 
to  give  up  to  cold  hydrochloric  acid  a  quantity  of  phos- 
phoric acid,  which,  calculated  per  hectare  to  a  depth  of 
25  centimetres,  amounted  to  2376  kilogrammes  =  5170 
kilogrammes  of  phosphate  of  lime. 

The  quantity  of  phosphoric  acid  in  the  corn  and 
straw  of  the  crop  reaped  amounted  together  to  : — 

kilogr.    Its. 

From  the  manured  plot 17*5 =38*5  of  phosphoric  acid. 

From  the  unmanured  plot 8'0=17*6  " 

Surplus  obtained  by  manuring 9'5  =  20'9  " 

In  the  657*4  kilogrammes  of  phosphorite  the  field 
received  altogether  241*4  kilogrammes  of  phosphoric 
acid ;  accordingly,  the  surplus  amounted  only  to  ^th 
of  the  phosphoric  acid  supplied  in  the  manure. 

There  is  nothing  surprising  in  this  result,  as  the  ad- 
ditional phosphoric  acid  was  not  given  to  the  plants  but 
to  the  whole  field.  Had  it  been  possible  to  surround 
each  root  with  so  much  phosphoric  acid  or  phosphate 
of  lime  as  the  surplus  crop  of  corn  and  straw  required 
for  its  formation,  9£  kilogrammes  of  phosphoric  acid 
would  have  sufficed  to  double  the  produce  of  the  Tin- 
manured  plot ;  but  in  the  way  in  wrhich  the  manure 
was  actually  applied,  every  part  of  the  field  received  an 
equal  share  of  phosphoric  acid. 

Thus,  of  the  total  amount  of  241*4  kilogrammes, 
only  9*5  kilogrammes  came  into  contact  with  the  roots 
of  the  plants,  the  remainder,  though  quite  suitable  for 
food,  remaining  inactive.  To  enable  the  plant  to  take 
up  one  p^art  of  phosporic  acid,  it  was  necessary  to  sup- 
ply the  field  with  five-and-twenty  times  this  quantity. 

On  the  other  hand,  the  effect  of  the  manure  appears 
out  of  all  proportion  greater  as  compared  with  the  store 
of  phosphoric  acid  in  the  field. 

The  quantity  of  phosphoric  acid  contained  in  the 
corn  and  straw  reaped  from  the  unmanured  plot  is  3  ^  «th 
of  the  total  amount  of  phosphoric  acid  in  the  field  ;  that 
in  the  surplus  crop  is  ^'3th  of  the  phosphoric  acid  sup- 


150     ACTION   OF   SOIL   ON   FOOD   OF   PLANTS   IN   MANUEE. 

plied  by  the  manure.  As  the  manured  plot  gave  dou- 
ble the  produce  of  the  unmanured,  the  effect  of  the 
phosphoric  acid  supplied  by  the  manure  is  apparently 
twelve  times  greater  than  that  of  the  acid  originally 
contained  in  the  soil. 

The  quantity  of  phosphoric  acid  supplied  (241*4:  kilo- 

frammes)  amounted  to  TV th  of  the  total  quantity  in  the 
eld  (2376  kilogrammes).  If  the  action  of  both  had  been 
alike,  the  surplus  crop  should  have  corresponded  to  the 
additional  supply,  but  instead  of  being  y^th  greater,  it 
was  double  the  crop  obtained  from  the  unmanured  plot. 

This  fact  is  explained  by  the  absorptive  number  of 
the  Schleissheim  soil  for  phosphoric  acid  or  phosphate 
of  lime. 

If  the  store  of  phosphoric  acid  in  the  field  had  been 
uniformly  distributed  in  the  form  of  phosphate  of  lime 
(5170  kilogrammes)  to  a  depth  of  25  centimetres  (9-8 
inches),  each  cubic  decimetre  (61  cubic  inches)  would 
contain  2070  milligrammes  (32  grains),  each  cubic  centi- 
metre about  2  milligrammes  of  phosphate  of  lime. 

The  field  was  manured  with  657*4  kilogrammes  of 
phosphorite  in  a  soluble  state,  corresponding  to  525 
million  milligrammes  (525  kilogrammes)  of  pure  phos- 
phate of  lime. 

As  determined  by  direct  experiments,  1  cubic  deci- 
metre of  Schleissheim  soil  absorbs  976  milligrammes  of 
phosphate  of  lime.  Each  square  decimetre  received  in 
the  manure  525  milligrammes,  which,  dissolved  by  rain 
water  in  its  descent  through  the  soil,  would  be  sufficient 
to  saturate  the  earth  fully,  with  phosphate  of  lime,  to  a 
depth  of  5*4  centimetres  (rather  more  than  2  inches),  or 
to  half-saturate  it  to  a  depth  of  10*8  centimetres.  Hence 
the  manuring  served  to  enrich  the  upper  layer  of  the 
soil  with  phosphate  of  lime,  not  to  the  extent  of  TVth, 
but  to  50  per  cent.,  and  the  greater  part  of  this  in  a 
state  available  for  the  nutrition  of  plants.  The  absorp- 
tive power  of  the  soil  explains,  therefore,  why  the  crops 
obtained  from  manured  fields  are  rather  in  proportion  to 
the  nutritive  substances  supplied  in  the  manure,  than  to 
the  store  of  these  elements  originally  present  in  the  soil. 


OPERATION   OF   MANURING   AGENTS. 


151 


The  operation  of  manuring  agents,  severally  or 
jointly  applied,  is  even  more  marked  upon  soils  which 
are  poorer  in  nutritive  substances  than  the  field  at 
Schleissheim  above  mentioned. 

The  following  results  were  obtained  on  a  field  broken 
up  for  the  purpose,  which  had  not  been  touched  by  the 
plough  for  fifteen  years,  and  had  served  as  a  pasture  for 
sheep.  The  entire  surface-layer  of  the  ground  at 
Schleissheim  is  6  inches  deep  at  most ;  below  this  there 
is  no  more  soil,  but  a  bed  of  rubble  stones,  which  might 
be  compared  to  a  sieve  with  meshes  an  inch  wide, 
through  which  the  water  runs  freely ;  the  crop  ob- 
tained from  the  unmaiiured  portion  will  give  some  idea 
of  its  sterility.  Another  portion  was  manured  with 
superphosphate  of  lime  ;  the  quantity  used  per  hectare 
(  —  2f  acres)  was  525  kilogrammes  (  =  10  cwt.)  of 
phosphorite  decomposed  by  sulphuric  acid,  containing 
193  kilogrammes  of  phosphoric  acid,  or  420  kilo- 
grammes (  =  8  cwt.)  of  phosphate  of  lime. 

Crop  of  winter-rye  in  1858  at  Schleissheim,  per 
hectare : — 


Total  crop. 

Corn. 

Straw. 

Manured  with  phosphor-" 
ite    (rendered   soluble 
by  sulphuric  acid)  = 
525-3   kilo.   (10  cwt.) 
containing  192'8  kilo.   - 
(3-8  cwt.)  P  05,  corre- 
sponding to  420  kilo. 
(8  cwt.)  of  pure  phos- 

Kilo.        Cwt. 
1995-4=391-0 

Kilo.        Cwt. 

654-2=128-0 
• 

Kilo.        Cwt. 
1341  -2=200-0 

Unmanured     

397-6—     (y.g 

115'0—     2'3 

282'6—     6'5 

Dr.  Zoeller  found  by  analysis  that  this  field  con- 
tained, per  hectare,  to  a  depth  of  6  inches,  only  727 
kilogrammes  (  —  14  cwt.)  of  phosphoric  acid. 

The  plot  manured  with  phosphoric  acid  produced 
six  times  more  corn  and  five  times  more  straw  than  the 
unmanured  plot.  It  will  be  observed  that,  however 


152      ACTION    OF    SOIL    ON   FOOD    OF   PLANTS    IN   MANURE. 

strikingly  the  action  of  manure  was  exhibited,  this 
more  abundant  crop  did  not  equal  that  in  the  experi- 
ment previously  mentioned  of  the  unmanured  plot  kept 
for  a  considerable  time  under  culture.  Upon  compar- 
ing the  amount  of  phosphoric  acid  contained  in  the  two 
fields,  we  find  that  as  the  sheep  pastures,  to  the  depth  of  6 
inches,  contained  only  half  as  much  as  the  other  (tilled 
but  unmanured),  the  dressing  with  superphosphate  was 
only  just  sufficient  to  make  the  sheep-meadow,  to  the 
depth  of  8  or  10  centimetres  (  =  3  to  4  inches),  equal 
to  the  other  unmanured  plot,  in  respect  of  the  phosphoric 
acid  contained  in  it. 

These  considerations  explain  how  it  is  that  by  the 
absorption  of  nutritive  substances  in  the  upper  layers 
of  the  soil  a  supply  of  these  constituents  or  manuring 
ingredients,  small  in  comparison  to  the  total  store  in  the 
ground,  exercises  so  remarkable  an  action  in  the  increase 
of  produce,  in  the  case  of  plants  which  draw  their  food 
chiefly  from  the  upper  layers  of  the  arable  surface  soil. 

If  the  action  of  the  mineral  constituents  depends 
upon  the  sum  of  effective  particles  in  certain  places  in 
the  soil,  the  action  rises  with  the  number  of  particles  by 
which  the  sum  has  been  increased  in  these  very  places. 

A  more  accurate  acquaintance  with  the  composition 
of  arable  surface  soil,  and  its  relation  to  the  nutritive 
substances,  together  with  a  consideration  of  the  nature 
and  requirements  of  plants,  must  gradually  lead  to  a 
comprehension  of  many  other  phenomena  in  agriculture, 
which  hitherto  are  quite  unexplained,  and  to  many 
farmers  are  absolute  mysteries.  Although  we  know 
most  accurately  the  general  laws  of  the  growth  of 
plants,  as  far  as  these  stand  in  connection  with  soil,  air, 
and  water,  yet  in  many  cases  it  is  extremely  difficult  to 
discover  the  causes  that  render  a  soil  unproductive  for 
one  culture-plant,  e.g.  peas,  while  the  same  soil  is  fruit- 
ful for  other  plants  which  require  the  same  nutritive 
substances  as  peas,  and  often  in  still  greater  quantity. 
If  the  ground  is  rich  enough  in  nutritive  substances  for 
these  other  plants,  why  is  it  that  they  do  not  act  in  the 
same  way  upon  the  peas  ?  What  causes  prevent  the 


DIFFICULTIES   NOT   ALWAYS   EXPLAINED.  153 

latter  from  appropriating  the  nutritive  substances, 
which  the  ground  offers  to  other  plants  in  a  perfectly 
available  condition  ?  Finally,  how  comes  it  that  this 
very  soil,  after  a  few  years,  will  again  yield  a^  remune- 
rative crop  of  peas,  although  by  intervening' harvests 
we  have  rather  impoverished  than  enriched  its  store  of 
nutritive  substances  ;  and  that  peas,  when  sown  among 
oats,  barley,  or  summer  corn,  will  often  yield  a  higher 
crop  than  when  they  grow  alone  upon  a  field,  and  have 
not  to  share  with  other  plants  the  store  of  mineral  con- 
stituents ? 

Analogous  facts  are  observed  in  the  cultivation  of 
clover.  In  many  districts,  a  field,  after  producing  many 
clover  crops,  will  become  almost  unfruitful  for  that 
plant. 

In  such  cases,  manuring  fails  in  restoring  to  the  field 
the  power  of  producing  clover  ;  but  after  several  years, 
during  which  the  same  field  continues  to  give  remu- 
nerative crops  of  cereal  and  tuberous  plants,  the  soil 
again  becomes  for  a  while  fruitful  for  clover. 

For  a  considerable  number  of  our  cultivated  plants 
we  have  a  pretty  accurate  knowledge  of  specific  manur- 
ing agents,  i.e.  those  which  have  a  peculiarly  favourable 
influence  upon  the  majority  of  fields.  Farm-yard  ma- 
nure, as  a  rule,  acts  beneficially  in  all  cases  ;  salts  of 
ammonia  are  especially  valuable  for  cereals,  superphos- 
phate of  lime  for  turnips ;  bone  earth  and  ashes  will 
perceptibly  increase  the  produce  of  fruitful  clover-fields, 
and,  in  like  manner,  a  supply  of  lime  will  often  make  a 
field  fruitful  for  clover,  though  otherwise  unable  to 
bear  it. 

But  upon  fields  which  have  become,  as  it  is  termed, 
peas  or  clover  sick,  that  is,  have  lost  their  power  of  pro- 
ducing these  plants,  all  these  matters  otherwise  favour- 
able for  their  growth  exercise  beyond  a  certain  time  no 
further  beneficial  action.  It  is  this  fact  in  particular 
which  embarrasses  the  practical  farmer,  and  makes  him 
doubt  the  lessons  taught  by  science. 

When  the  farmer  is  compelled  to  give  up  for  many 
years  the  cultivation  of  plants  which  he  had  found  re- 
7* 


* 
154     ACTION   OF   SOIL  ON  FOOD   OF  PLANTS   IN  MANURE. 

munerative,  and  science  has  no  power  to  help  him  over 
his  difficulties,  what  is  the  use  of  theory  ?  So  says  the 
agriculturist  who  is  himself  unacquainted  with  the 
essence  of  theory. 

It  is  a  common  error  to  fancy  that  an  accurate 
knowledge  of  theory  will  give  the  power  of  explaining 
all  cases  that  occur.  Theory  of  itself  does  not  explain 
a  single  phenomenon  in  astronomy,  mechanics,  physics, 
or  chemistry ;  it  studies  and  points  out  the  causes  which 
lie  at  the  foundation  of  all  phenomena,  not  the  special 
causes  upon  which  an  individual  phenomenon  depends. 

Theory  requires  that  the  causes  which  govern  each 
individual  case  should  be  sought  out  one  by  one,  and 
then  the  explanation  is  the  proof  or  exposition  of  the 
manner  in  which  they  work  together  to  produce  the 
particular  fact.  It  teaches  us  what  to  look  for,  and  how 
to  employ  proper  experiments  in  the  discovery. 

The  reason  why  we  have  arrived  at  no  conclusions 
about  the  facts  just  mentioned,  depends  chiefly  upon 
this,  that  hitherto  the  practical  farmer  has  troubled 
himself  very  little  about  the  causes  of  those  facts,  as, 
indeed,  the  investigation  of  causes  is  not  his  proper 
business ;  while  those  who  have  undertaken  this  task 
show,  by  the  way  in  which  they  attempt  to  discharge 
it,  that  they  are  but  little  acquainted  with  the  plant  as 
an  organised  being,  having  peculiar  requirements  which 
must  be  accurately  known  by  all  who  would  cultivate 
it  properly. 

In  the  following  remarks  I  shall  compare  a  pea- 
plant  with  a  cereal,  and  shall  call  the  attention  of  agri- 
culturists to  certain  peculiarities  which  have  to  be  con- 
sidered in  the  cultivation  of  both  plants. 

A  moderately  moist,  strong  soil,  not  too  cohesive 
and  perfectly  free  from  weeds,  is  particularly  suited  for 
peas  and  barley  ;  a  well-tilled,  calcareous  loam  or  marl 
is  the  best  for  both  plants.  An  arable  surface  soil  6 
inches  deep  suffices  for  barley,  which,  with  its  fine- 
inatted  roots  spreading  in  tufts,  finds  a  loose  subsoil 
rather  injurious  than  beneficial.  Fresh  manuring  just 
before  sowing  acts  powerfully  on  the  growth  of  barley. 


GROWTH   OF  PEA  AND  BAKLEY   COMPARED.  155 

Whilst  the  barley-corn  should  not  lie  lower  than  an 
inch,  the  pea  thrives  best  if  the  seed  is  put  2  or  3  inches 
deep  in  the  soil.  The  roots  of  the  pea-plant  do  not 
spread  sideways  but  go  deep  into  the  earth  ;  hence  peas 
require  a  deep  soil  tilled  down  to  the  lower  layers,  and 
a  loose  subsoil.  Fresh  manure  has  scarcely  any  in- 
fluence upon  the  growth  of  peas. 

It  results  from  these  peculiarities  of  both  plants,  that 
the  barley  derives  the  conditions  of  its  growth  princi- 
pally from  the  arable  surface  soil,  the  pea  principally 
from  the  deeper  layers  of  the  soil.  What  the  ground 
may  contain  below  the  depth  of  6  inches  is  a  matter  of 
indifference  for  the  barley  ;  the  contents  of  these  deeper 
layers  are  everything  to  the  pea. 

If  we  now  inquire  what  demands  are  made  upon  the 
soil  by  the  two  plants,  we  find  from  Mayer's  investiga- 
tions ('  Results  of  Agricultural  and  Chemical  Experi- 
ments, Munich,  1857,'  p.  35),  that  the  pea-seeds  contain 
one-third  more  ash  constituents  (3.5  per  cent.)  than  the 
barley-corns,  and  that  the  amount  of  phosphoric  acid  is 
pretty  much  the  same  in  both  (2*7  per  cent.).  There- 
fore, all  other  conditions  being  equal,  the  subsoil  from 
which  the  pea  derives  its  phosphoric  acid  must  be  as  rich 
in  that  ingredient  as  the  arable  surface  soil  which  sup- 
plies it  to  the  barley. 

The  case  is  different  with  nitrogen — for  the  same 
amount  of  phosphoric  acid,  peas  contain  nearly  twice  as 
much  nitrogen  as  barley.  Assuming  both  plants  to 
derive  their  nitrogen  from  the  soil  (which  is,  perhaps, 
not  quite  correct  in  the  case  of  peas),  then  for  every 
milligramme  of  nitrogen  absorbed  by  the  roots  of  the 
barley  from  the  arable  surface  soil,  twice  as  much  must 
be  received  by  the  peas  from  the  deeper  layers. 

These  considerations  throw  some  light,  I  think,  upon 
the  cultivation  of  peas  ;  for  this  plant  requires  a  very 
peculiar  condition  of  the  soil ;  and  it  is  more  easy  to 
conceive  that  a  ground  exhausted  by  bearing  peas 
should  refuse  to  bear  any  more,  than  that  the  same  soil, 
after  the  lapse  of  some  years,  should  again  become  fruit- 
ful for  this  plant. 


156     ACTION    OF    SOIL   ON   FOOD   OF   PLANTS   IN  MANURE. 

According  to  these  considerations,  and  assuming  an 
equality  of  the  absorbent  root-surface  in  both  plants,  a 
subsoil  fruitful  for  peas  must  contain  as  much  phos- 
phoric acid,  and  twice  as  much  nitrogen,  as  an  arable 
surface  soil  suited  for  the  cultivation  of  barley.  For 
the  phosphoric  acid,  the  assumption  is  correct. 

We  understand,  without  difficulty,  the  beneficial 
effect  of  manure  upon  an  exhausted  barley  field.  Bar- 
ley derives  all  the  conditions  of  healthy  growth  from 
the  surface  soil,  which  is  restored  to  its  original  state  of 
productiveness  by  the  manure  applied. 

But  from  our  acquaintance  with  the  properties  pecu- 
liar to  arable  soil,  we  know  that  a  layer  6  to  10  inches 
deep  will  retain  all  the  ammonia  potash  and  phosphoric 
acid  contained  in  the  largest  quantity  of  manure  usually 
applied  by  farmers  ;  and  this,  too,  so  firmly  that,  except 
for  some  accidentally  favourable  circumstances,  hardly 
a  particle  will  ever  reach  the  subsoil. 

If  a  field  is  sown  with  plants  which  require  deep 
ploughing,  so  that  a  sufficient  portion  of  the  rich  sur- 
face is  mixed  with  the  exhausted  subsoil,  it  is  easy  to 
understand  that  the  latter  may  gradually  become  again 
fruitful  for  peas.  The  time  in  which  this  is  effected 
depends  of  course  upon  the  accidental  selection  of  the 
plants  grown  in  succession  on  the  field. 

In  this  view  of  the  matter,  the  agriculturist  has  it  in 
his  power,  by  right  management  of  his  field,  to  shorten 
the  time,  and  make  the  land  again  fit  for  successive 
crops  of  peas. 

It  is  a  fact,  that  many  fields  in  the  vicinity  of  towns 
will  bear  year  after  year,  or  every  two  years,  abundant 
crops  of  peas,  without  ever  becoming  '  pea-sick  ; '  and 
we  know  that  the  gardener,  to  achieve  this  result,  has 
recourse  to  no  extraordinary  appliances,  but  merely  tills 
his  land  deep  and  very  carefully,  using  much  more 
manure  than  the  farmer  can  afford  to  do. 

The  frequent  failure  of  peas  is  therefore  not  so  very 
unaccountable ;  and  there  seems  no  reason  why  the 
farmer  should  despair  of  cultivating  peas  as  often  as 
serves  his  purpose,  if  he  employ  the  right  means  to 


A   CLOVER-SICK   FIELD.  ,          157 

enrich  his  field  in  the  proper  spots  with  the  elements 
of  food  which  peas  require. 

In  all  problems  of  this  kind,  the  secret  of  success  is, 
not  to  suppose  that  the  solution  is  easy,  but  that  it  is 
attended  with  great  difficulties ;  for,  if  these  did  not 
exist,  experimental  art  would  long  ago  have  found  the 
solution. 

The  many  unsuccessful  experiments  of  Messrs.  Lawes 
and  Gilbert  to  make  a  clover-sick  field  again  productive 
for  clover,  have  a  certain  value,  in  as  far  as  they  show 
that  mere  experimenting  leads  to  nothing.  If  I  here 
bestow  upon  these  experiments  an  attention  which  they 
do  not  deserve,  my  object  is,  not  to  submit  them  to  a 
passing  criticism,  but  to  warn  the  practical  man  how  he 
ought  not  to  proceed  in  trying  to  solve  his  problems, 
if  he  wishes  that  his  efforts  should  meet  with  success. 
The  conclusions  which  Messrs.  Lawes  and  Gilbert  have 
drawn  from  their  numerous  experiments  are  as  fol- 
lows : — they  found  that  when  land  is  not  yet  clover- 
sick,  the  crop  may  frequently  be  increased  by  manuring 
with  salts  of  potash  and  superphosphate  of  lime ;  that 
when,  on  the  contrary,  the  land  is  clover-sick,  none  of 
the  ordinary  manures,  whether  '  artificial '  or  '  natural,' 
can  be  relied  upon  to  secure  a  crop  ;  and  that  the  only 
way  is  to  wait  some  years  before  repeating  red  clover  on 
the  same  land. 

It  is  hardly  necessary  to  remark,  that  what  Messrs. 
Lawes  and  Gilbert  are  here  pleased  to  call  conclusions, 
are  no  conclusions  at  all ;  what  they  have  discovered 
has  been  experienced  by  thousands  of  agriculturists  be- 
fore them  ;  and  the  only  conclusion  which  they  were 
permitted  to  draw  should  have  been  this — that  in  their 
attempts,  by  certain  manures,  to  make  a  clover-sick 
field  again  productive  for  clover,  they  failed.  In  truth, 
they  have  not  striven,  in  the  remotest  degree,  to  pro- 
cure information  about  the  causes  of  clover-sickness  in  a 
field,  but  they  have  simply  tried  different  manures,  in 
the  hope  of  finding  out  one  that  might  serve  to  restore 
the  original  productive  power  of  the  field,  and  such  a 
manure  they  have  not  found. 


158    ACTION    OF    SOIL    ON   FOOD   OF    PLANTS    IN    MANURE. 

Messrs.  Lawes  and  Gilbert  assume  that,  with  respect 
to  the  soil,  the  clover  plant  bears  the  same  relation  as 
wheat  or  barley  ;  and  finding  that  on  a  field  (whereon, 
notwithstanding  the  richest  manure,  clover  had  failed) 
an  abundant  barley  or  wheat  crop  was  obtained  the 
year  after,  it  became  a  settled  conviction  with  them 
that  the  failure  of  the  clover  had  been  caused  by  a  spe- 
cific disease  generated  in  the  soil  by  the  cultivation  of 
clover  ;  this  disease  would  attack  the  clover  plant,  but 
not  the  roots  of  wheat  or  barley. 

Clover  differs  entirely  from  the  cereal  plants  in  this 
respect,  that  it  sends  its  main  roots  perpendicularly 
downwards,  when  no  obstacles  stand  in  the  way,  to  a 
depth  which  the  fine  fibrous  roots  of  wheat  and  barley 
fail  to  reach  ;  the  principal  roots  of  clover  (as  may  be 
seen  more  especially  with  TrifoUum  pratense)  branch 
off  into  creeping  shoots,  which  again  send  forth  fresh 
roots  downwards. 

Thus  clover,  like  the  pea-plant,  derives  its  principal 
food  from  the  layers  below  the  arable  surface  soil ; 
and  the  difference  between  the  two  consists  mainly  in 
this — that  the  clover,  from  its  larger  and  more  exten- 
sive root-surface,  can  still  find  a  sufficiency  of  food  in 
fields  where  peas  will  no  longer  thrive :  the  natural 
consequence  is,  that  the  subsoil  is  left  proportionably 
much  poorer  by  clover  than  by  the  pea. 

Clover-seed,  on  account  of  its  small  size,  can  furnish 
from  its  own  mass  but  few  formative  elements  for  the 
young  plant,  and  requires  a  rich  arable  surface  for  its 
developement ;  but  the  plant  takes  comparatively  little 
food  from  the  surface  soil.  When  the  roots  have 
pierced  through  this,  the  upper  parts  are  soon  covered 
with  a  corky  coating,  and  only  the  fine  root-fibres  rami- 
fying through  the  subsoil  convey  food  to  the  plant. 

$Tow,  if  we  look  at  the  experiments  made  by  Messrs. 
Lawes  and  Gilbert  to  render  a  clover-sick  field  produc- 
tive again  for  clover,  we  see,  at  once,  that  all  the  means 
employed  were  well  adapted  to  enrich  the  uppermost 
layers  of  their  field  with  nutritive  substances  for  wheat 
and  barley  ;  but  that  the  clover  plant  could  derive  ben- 


A   CLOVEK-SICK   FIELD.  159 

efit  from  this  manuring  only  in  the  first  stage  of  devel- 
opement,  while  the  condition  of  the  lower  layers  re- 
mained unaltered,  just  as  if  the  field  had  received  no 
nutriment  of  any  kind. 

The  manures  applied  by  Messrs.  Lawes  and  Gilbert 
were  superphosphates  of  lime  (300  Ibs.  of  bone-earth 
and  225  Ibs.  of  sulphuric  acid  per  acre) ;  sulphate  of 
potash  (500  Ibs.) ;  sulphate  of  potash  and  superphos- 
phate, mixed  alkaline  salts  (500  Ibs.  of  sulphate  of  pot- 
ash, 225  Ibs.  of  sulphate  of  soda,  100  Ibs.  of  sulphate  of 
magnesia) ;  mixed  alkalis  with  superphosphate ;  fur- 
ther, salts  of  ammonia  alone,  and  the  same  salts  with 
superphosphate  or  mixed  alkalis ;  farm-yard  manure 
(15  tons),  together  with  lime,  or  with  lime  and  super- 
phosphate, or  with  lime  and  alkalis  in  the  most  varied 
proportions ;  then  soot ;  soot  with  lime ;  soot  with 
lime,  alkalis,  and  superphosphate.  None  of  these  ma- 
nures had  the  slightest  effect ;  the  clover-sick  field  con- 
tinued just  as  unproductive  for  clover  as  before. 

The  reason  why  these  manures  were  inoperative  is 
not  difficult  to  find.  Messrs.  Lawes  and  Gilbert,  in 
their  report,  leave  us,  indeed,  in  the  dark  as  to  the  na- 
ture and  condition  of  the  soil  upon  which  their  experi- 
ments were  made ;  but  from  some  incidental  observa- 
tions in  previous  papers,  we  know  that  the  fields  at 
Rothamstead  consist  of  a  rather  heavy  loam,  very  well 
suited  for  cereals,  and  especially  for  barley. 

From  experiments  upon  the  absorptive  power  of 
loam,  we  may  assume,  without  risk  of  error,  that  one 
cubic  decimetre  (=61  cubic  inches  of  loam)  will  absorb 
2000  milligrammes  (=31  grains  of  potash),  and  1000 
milligrammes  (=15*5  of  phosphate  of  lime). 

The  surface  of  an  acre  of  loam  (—405,000  square 
decimetres)  will  therefore  absorb  to  a  depth  of  1  deci- 
metre (=4:  inches)  805  kilogrammes  (=1,771  Ibs.)  of 
potash,  and  405  kilogrammes  (=891  Ibs.)  of  phosphate 
of  lime. 

The  most  copious  dressing  with  sulphate  of  potash 
which  Messrs.  Lawes  and  Gilbert  gave  to  their  field 
amounted  to  500  Ibs.  (  =270  Ibs.)  of  potash  ;  the  most 


160     ACTION   OF   SOIL   ON  FOOD   OF  PLANTS   IN   MANURE. 

copious  of  the  superpliospate  dressings  represented  300 
pounds  of  phosphate  of  lime. 

Had  Messrs.  Lawes  and  Gilbert  put  upon  the  field 
the  sulphate  of  potash  and  the  phosphate  of  lime  in  a 
state  of  complete  solution,  the  whole  quantity  of  potash 
employed  would  have  penetrated  no  deeper  than  2  cen- 
timetres, or  not  quite  an  inch,  and  the  phosphate  of 
lime  no  deeper  than  4  centimetres,  or  a  little  more  than 
1*6  inch.  Both  manures,  however,  were  strewed  over 
the  field  and  ploughed  in ;  still  it  cannot  be  assumed 
that  the  layers  below  a  depth  of  8  inches  could  have 
received  any  considerable  quantity  of  potash  or  phos- 
phate of  lime. 

At  page  10  of  their  paper  (<  Report  of  experiments 
on  the  growth  of  red  clover  by  different  manures') 
Messrs.  Lawes  and  Gilbert  say,  '  Those  who  have  paid 
attention  to  the  spread  of  disease  in  clover,  on  land 
which  is  said  to  be  clover-sick,  will  have  observed,  that 
however  luxuriant  the  plant  may  be  in  the  autumn  and 
winter,  it  will  show  signs  of  failure  in  March  or  April.' 
The  same  fact  was  observed  in  all  their  experiments. 
A  field  on  which  clover  had  failed  was  sown  with  bar- 
ley, and  when  this  had  yielded  a  rich  crop,  another 
attempt  was  made  with  clover. 

1  The  plants  (say  Messrs.  Lawes  and  Gilbert)  stood 
tolerably  well  during  the  winter,  but  as  the  spring  ad- 
vanced they  died  off  rapidly.'  There  cannot  be  the 
slightest  doubt  about  the  reason  of  this  decay  ;  the  ex- 
hausted subsoil  had  not  received  back  any  of  the  lost 
conditions  of  fertility,  and  thus  the  plants  were  starved 
as  soon  as  they  had  pushed  through  the  arable  surface 
soil,  and  their  roots  were  beginning  to  spread  in  the 
subsoil. 

If  the  failure  of  the  clover  was  .attributable  to  a  dis- 
ease, this  must  have  been  of  a  very  singular  nature,  as 
the  richly-manured  arable  soil  showed  no  traces  of  it, 
and  it  was  only  the  subsoil  which  was  clover-sick.  The 
notion  that  there  is  any  disease  engendered  by  the  cul- 
tivation of  clover  is  refuted  most  completely,  though 
unconsciously,  by  Messrs.  Lawes  and  Gilbert  them- 


(  V 


CAUSE  OF  THE  FAILURE  OF  CLOVER.        161 

selves.  They  say,  page  17,  '  Before  we  enter  upon  the 
probable  causes  of  the  failure  in  clover,  it  may  be  well 
to  give  the  results  of  some  experiments  conducted  in 
the  kitchen-garden  at  Kothamstead.  The  soil  was  in 
ordinary  garden  cultivation,  and  has  probably  been  so 
for  two  or  three  centuries.  Early  in  1854,  the  s^th 
of  an  acre  (about  9f  square  yards)  was  measured  off 
and  sown  with  red  clover  on  March  29.  From  that 
time  to  the  end  of  1859  fourteen  cuttings  have  been 
taken  without  any  resowing  of  seed.  In  1856  this  little 
plot  was  divided  into  three  equal  portions,  of  which  one 
was  manured  with  gypsum,  another  with  sulphates  of 
potash,  soda,  and  magnesia,  and  superphosphate  of 
lime.' 

'  The  estimated  total  amount  of  green  clover  ob- 
taied  from  this  garden  soil  in  six  years,  without  further 
manure,  is  about  126  tons  per  acre,  equal  to  about  26-J 
tons  of  hay.  In  four  years  the  increase  by  the  use  of 
gypsum  amounted  to  15-J-  tons  of  green  clover.  The 
increase  in  the  four  years  by  the  use  of  the  alkalis  and 
phosphate  is  estimated  to  amount  to  28f  tons  of  green 
produce.' 

4  It  is  worthy  of  remark,'  continues  the  report,  c  that 
it  was  in  some  of  the  very  same  seasons  in  which  these 
heavy  crops  of  clover  were  obtained  from  the  garden 
soil,  that  we  entirely  failed  to  get  anything  like  a  mod- 
erate crop  of  clover  in  the  experimental  field,  only  a 
few  hundred  yards  distant.' 

It  is,  indeed,  most  worthy  of  remark,  that  upon  the 
experimental  field  the  earth  was  poisoned  by  the  vege- 
tation of  the  clover,  so  as  to  render  it  incapable  of  fur- 
ther bearing  this  plant ;  while,  at  the  very  same  time, 
under  like  climatic  conditions,  the  self-same  clover-plant 
engendered  no  poison  in  the  rich  garden  soil. 

A  comparative  examination  of  the  garden  and  of  the 
field-soil  seems  never  to  have  been  thought  of,  since  the 
two  agricultural  chemists  were,  as  we  before  remarked, 
in  search  of  an  efficient  manure,  not  of  the  cause  of  the 
failure  of  the  plant.  But  though  they  have  not  found 
the  smallest  shred  of  a  fact  which  might  serve  in  any 


162     ACTION    OF   SOIL   ON   FOOD   OF   PLANTS   IN   MANURE. 

way  to  explain  the  strange  behaviour  of  the  clover-plant 
upon  the  two  fields,  they  do  not  hesitate  to  present  the 
farmer  with  the  following  ingenious  explanation  : — 

'  Among  plants,'  say  they,  '  there  are  certain  kinds 
which  are  peculiarly  circumstanced  with  respect  to  the 
nature  of  their  food ;  the  cereals,  among  others,  feed 
principally  upon  inorganic  matters,  whilst  others,  the 
leguminous  plants,  e.  g.  clover,  are  dependent  for  luxu- 
riant growth,  more  or  less,  upon  a  supply  within  the 
soil  of  complex  organic  compounds.' 

Taking  their  stand  upon  the  fact  that  they  have 
failed  to  discover  any  explanation,  which,  in  their 
opinion,  they  surely  must  have  done,  had  it  been  pos- 
sible to  find  one,  they  coolly  ask  us  to  believe  that 
there  are,  among  the  higher  classes  of  plants,  certain 
species  bearing  about  the  same  relation  to  other  species 
as  the  carnivorous  to  the  graminivorous  animals ;  and 
as  the  former  feed  upon  complex  organic  compounds 
prepared  in  the  bodies  of  the  latter,  so  it  is,  also,  with 
the  clover-plant ;  like  mushrooms,  it  represents  the  car- 
nivorous order  in  the  vegetable  kingdom. 

It  is  hardly  worth  while  to  take  any  notice  of  this 
explanation  ;  but  it  might  still  prove  useful  to  inquire 
whether,  apart  from  all  consideration  of  the  absorptive 
power  of  the  soil,  Messrs.  Lawes  and  Gilbert  have  really 
exhausted  all  the  means  that  might  have  been  employed 
to  restore  the  productiveness  of  the  clover-sick  field  for 
clover,  so  as  to  be  justified  in  giving  it  as  their  opinion 
that  when  land  is  clover-sick,  none  of  the  ordinary  ma- 
nures, artificial  or  natural,  can  be  relied  upon  to  secure 
a  crop. 

We  may  ask  why  Messrs.  Lawes  and  Gilbert  did 
not,  instead  of  superphosphate  of  lime,  try  bone  ash, 
the  action  of  which  extends  much  deeper  than  that  of 
the  superphosphate ;  and  why  sulphate  of  potash  and 
sulphates  alone  were  employed  ?  It  is  not  impossible 
that  common  wood  ashes  might  have  proved  more 
effective  than  sulphate  of  potash  ;  and,  above  all,  chlo- 
ride of  potassium  ought  to  have  been  tried,  which,  as 
an  ingredient  of  liquid  manure,  is  more  useful  to  clover 


EXPLANATION   OF   THE   FAILURE   OF   CLOVES.          163 

than  any  oilier  of  the  potash  salts.  It  is  also  difficult 
to  understand  why  liquid  manure  was  not  employed, 
and  why  chloride  of  sodium  was  excluded  from  the  list 
of  manuring  agents.  If  we  consider  what  Messrs. 
Lawes  and  Gilbert  omitted  to  do  in  their  endeavour  to 
solve  the  problem,  and  what  they  ought  to  have  done, 
the  conclusion  is  inevitable,  that  they  had  no  accurate 
notion  of  the  nature  of  their  task. 

JSTow,  the  want  of  a  proper  insight  into  the  nature 
of  a  phenomenon  which  is  to  be  investigated  is  surely 
the  greatest  of  all  difficulties  in  the  way  of  attaining  a 
practical  result.  If  the  unproductiveness  of  a  field  for 
clover  and  peas  depends  upon  a  want  of  nitrogenous 
food  in  the  deeper  layers  of  the  soil,  and  upon  no  other 
cause,  the  absorptive  power  of  the  various  soils  for  am- 
monia renders  it  extremely  difficult  to  enrich  the  sub- 
soil with  this  element  of  food.  But  the  case  is  quite 
different  with  the  nitrates,  which  penetrate  to  any 
depth,  as  the  nitric  acid  is  not  absorbed  by  the  soil ; 
probably,  nitrate  of  soda  may  afford  a  means  of  making 
a  field  productive  for  clover  or  peas,  in  cases  where 
there  is  a  deficiency  of  nitrogenous  food. 

As  manuring  with  burnt  lime  is  often  found  bene- 
ficial for  clover  and  also  for  peas,  and  a  calcareous  soil 
tends,  in  a  special  degree,  to  promote  the  formation  of 
nitric  acid,  it  is  not  improbable  that  it  is  owing  to  this 
property  that  lime  promotes  the  growth  of  deep-rooting 
plants  by  converting  ammonia  into  nitric  acid,  and 
causing  nitrogenous  food  to  find  its  way  to  the  deeper 
layers  of  the  soil. 


CHAPTER  IY. 

FAKM-YAKD     MANURE. 

The  fertility  of  a  soil  depends  upon  the  sum  of  available  food,  the  continuance  of 
the  fertility  upon  the  total  amount  of  all  food  in  it— Chemical  and  agricultural 
exhaustion  of  the  soil— Exhaustion  of  the  soil  by  cultivation,  laws  regulating 
its  progression  •  effect  of  the  transformation  in  the  soil  of  the  chemically  fixed 
into  physically  fixed  elements  of  food  ;  effect  on  the  progress  of  exhaustion  by 
partial  restoration  of  the  withdrawn  food  of  plants— Progress  of  the  exhaustion 
by  different  cultivated  plants — Cultivation  of  cereals,  consequence  of  removing 
the  grain  and  leaving  the  straw  in  the  soil  ;  intervening  clover  and  potato 
crops  ;  effect  of  leaving  in  the  ground  the  whole  or  a  portion  of  these  crops  ; 
division  of  soils  ;  productive  power  of  wheat  fields  increased  by  accumulating 
in  them  the  materials  derived  from  clover  and  potato  fields  ;  cultivation  of 
fodder  plants  ;  their  food  partly  derived  from  the  subsoil ;  addition  of  these  in- 
creases the  productive  power  of  the  surface  soil — Natural  connection  between 
the  cultivation  of  cereals  and  fodder  plants,  the  influence  on  the  fertility  of 
land— Exhaustion  of  the  soil  removed  by  the  restoration  of  the  withdrawn 
mineral  constituents  ;  the  excrement  of  men  and  animals  contains  these  ;  their 
restoration  depends  upon  the  agriculturist. 

TO  form  a  correct  idea  of  the  effects  produced  by 
farm-yard  manure  in  husbandry,  it  must  be  remem- 
bered that  the  fertility  of  a  soil  is  always  exactly  pro- 
portionate to  the  amount  which  it  contains  of  nutritive 
substances  in  a  state  of  physical  combination  ;  and  that 
the  permanence  of  its  fertility  or  its  productive  power 
stands  in  proportion  to  the  total  quantity  of  the  con- 
stituents in  the  soil  capable  of  passing  over  into  that 
physical  condition. 

The  amount  of  crop  reaped  from  a  field  in  a  given 
time  is  proportionate  to  that  fraction  of  the  total  con- 
stituents which  has  passed  during  this  time  from  the 
ground  into  the  plants  grown  upon  it.  If  one  of  two 
fields  yields  twice  as  large  a  crop  of  wheat  and  straw  as 
the  other,  this  necessarily  presupposes  that  the  wheat- 
plants  upon  the  one  field  have  received  from  the  ground 
twice  as  much  nutriment  as  those  upon  the  other. 


CHEMICAL  AND  AGKICULTUEAL  EXHAUSTION.         165 

If  the  same  or  different  plants  are  cultivated  in  suc- 
cession on  a  field,  the  crops  will  gradually  decrease, 
and  the  soil  will  be  termed  '  exhausted,'  in  an  agricul- 
tural sense,  when  the  crops  cease  to  be  remunerative,  i  e. 
do  not  cover  the  expense  of  labour,  interest  of  money, 
&c.  As  the  high  crops  were  caused  by  the  soil  giving  to 
the  plant  a  certain  number  of  parts  from  the  total  nutri- 
tive substances,  just  so  the  exhaustion  of  the  field  pro- 
ceeds from  a  diminution  in  the  sum  of  those  nutritive 
substances. 

The  same  number  of  plants  cannot  thrive  upon  the 
same  field  as  formerly,  if  the  same  quantity  of  nutritive 
substances  enjoyed  by  the  previous  crop  is  no  longer  to 
be  found.  The  exhaustion  of  a  cultivated  field  in  a 
chemical  sense  differs  from  the  agricultural  use  of  the 
term  in  this,  that  the  former  refers  to  the  total  amount 
of  nutritive  substances  in  the  soil,  the  latter  to  that 
portion  only  of  the  total  amount  which  the  ground  can 
furnish  to  plants.  A  field  is  termed  exhausted  in  a 
chemical  sense  when  it  altogether  fails  to  produce  any 
more  crops. 

Of  two  fields,  one  of  which  contains,  to  the  same 
depth,  a  hundred  times,  the  other  only  thirty  times,  the 
amount  of  food  required  by  a  full  wheat  crop,  the  for- 
mer furnishes  to  the  roots  of  the  plants  more  nutriment 
than  the  latter  in  the  proportion  of  10 :  3,  supposing 
the  condition  and  mixture  of  the  soil  to  be  the  same  in 
both  cases.  If  the  roots  of  a  plant  receive  from  certain 
spots  of  the  one  field  10  parts  by  weight  of  nutriment, 
the  roots  of  the  same  plant  will  find  upon  the  other 
field  only  3  such  parts  available  for  absorption. 

An  average  wheat  crop  of  2000  kilogrammes  (  =  39 
cwts.)  of  grain,  and  5000  kilogrammes  (  —  98  cwts.) 
of  straw,  receives  from  a  hectare  (  —  2-J-  acres)  of  ground 
250  kilogrammes  (  —  5  cwts.)  of  ash-constituents  on, 
an  average.  Now,  upon  the  supposition  that  a  field, 
to  give  an  average  crop,  must  contain  100  times  that 
quantity  (or  25,000  kilogrammes)  of  ash-constituents  in 
a  perfectly  available  state,  it  follows  that  such  a  field 
gives  1  per  cent,  of  its  total  store  to  the  first  crop. 


166  FARM-YABD  MANURE. 

The  soil  will  still  continue  productive  for  new  wheat 
crops  in  the  following  years ;  but  the  amount  of  prod- 
uce will  gradually  decrease. 

If  the  soil  is  most  carefully  mixed,  the  wheat  plants 
will,  in  the  next  year,  find  everywhere  upon  the  same 
field  1  per  cent,  less  nutriment,  and  the  produce  in  corn 
and  straw  must  be  smaller  in  the  same  proportion.  If 
the  climatic  conditions,  the  temperature,  and  the  fall  of 
rain  remain  the  same,  there  will  be  reaped  from  the 
field  in  the  second  year  only  1980  kilogrammes  of  grain, 
and  4950  kilogrammes  of  straw  ;  and  in  each  succeed- 
ing year  the  crop  must  fall  off  in  a  fixed  ratio. 

If  the  wheat  crop  in  the  first  year  took  away  250 
kilogrammes  of  ash-constituents,  and  the  soil-  contained 
per  hectare  to  the  depth  of  12  inches  one  hundred  times 
that  quantity  (25,000  kilogrammes),  there  would  remain 
in  the  ground  at  the  end  of  the  thirtieth  year  of  culti- 
vation 18,492  kilogrammes  of  nutritive  substances. 

Whatever  variations  in  the  amount  of  produce 
may  have  been  caused  by  climatic  conditions  during 
the  intervening  years,  it  is  evident  that  in  the  thirty- 
first  year,  if  there  has  been  no  restoration  of  mineral 
matters,  the  field  will  produce,  even  under  the  most 
favourable  circumstances,  only  iff  —  0*74,  or  some- 
what less  than  three-fourths  of  an  average  crop. 

If  these  three-fourths  of  an  average  crop  do  not  give 
the  farmer  a  sufficient  excess  of  income  over  expen- 
diture, if  they  barely  cover  his  outlay,  the  crop  can  no 
longer  be  called  remunerative.  He  calls  his  field  '  ex- 
hausted '  for  the  cultivation  of  wheat,  although  it  con- 
tains seventy-four  times  the  quantity  of  nutritive  sub- 
stances required  by  an  average  crop  for  the  year. 
,Owing  to  the  presence  of  the  entire  sum  of  nutritive 
substances,  in  the  first  year  of  cultivation  each  root 
found,  in  the  parts  of  the  soil  in  contact  with  it,  the 
requisite  amount  of  mineral  food  for  its  complete  devel- 
opement ;  but,  owing  to  the  continuous  crops,  only 
three-fourths  of  this  quantity  is  found  in  the  thirty- 
first  year  in  the  same  portions  of  the  soil. 

An  average  crop  of  rye  (1600  kilogrammes  (  = 


REMUNERATIVE  OAT  CROP  AFTER  RYE.       167 

cwts.)  of  grain,  and  3800  kilogrammes  (  =  74rJ  cwts.)  of 
straw)  takes  away  from  the  ground  per  hectare  only  180 
kilogrammes  (  =  3^  cwt.)  of  ash-constituents. 

If  the  production  of  an  average  wheat  crop  requires 
the  presence  in  the  soil  of  25,000  kilogrammes  of  the 
ash-constituents  of  wheat  plants,  a  soil  with  only  18,000 
kilogrammes  of  such  constituents  will  prove  sufficiently 
rich  to  give  an  average  and  a  succession  of  remunera- 
tive crops  of  rye. 

By  our  reckoning,  a  field,  though  exhausted  for  the 
cultivation  of  wheat,  still  contains  18,492  kilogrammes 
of  mineral  constituents,  the  same  in  properties  as  those 
which  the  rye  plant  requires. 

If  it  is  asked  after  how  many  years  continuous  rye- 
cultivation  the  average  crop  will  sink  down  to  a  three- 
quarter  crop,  assuming  this  to  be  no  longer  remunera- 
tive, we  find  that  the  field  will  produce  28  remunerative 
rye-crops,  and  after  28  years  will  be  exhausted  for  its 
cultivation. 

The  nutritive  substances  yet  remaining  in  the  soil 
will  still  amount  to  13,869  kilogrammes  of  ash-con- 
stituents. 

A  field  on  which  rye  can  no  longer  be  cultivated 
with  profit  is  not  on  that  account  unfruitful  for  oats. 

An  average  crop  of  oats  (2000  kilogrammes  (  =  39 
cwts.)  of  grain,  and  3000  kilogrammes  (  =  59  cwts.)  of 
straw)  takes  from  the  soil  310  kilogrammes  (  =  6  cwts.) 
of  ash-constituents,  being  60  kilogrammes  (  =  1*2  cwt.) 
more  than  is  removed  by  a  wheat  crop,  and  130  kilo- 
grammes (  =  2|-  cwts.)  more  than  by  a  rye  crop.  If 
the  absorbent  root-surface  of  the  oat  plant  were  the 
same  as  that  of  rye,  oats  after  rye  would  not  yield  a 
remunerative  harvest ;  for  a  soil  supplying,  for  the, 
production  of  a  crop  of  oats,  310  kilogrammes  out  of  a 
stock  of  13,869  kilogrammes,  loses  thereby  2'23  per 
cent,  of  its  store  of  mineral  constituents,  whereas  the 
roots  of  rye  extract  only  1  per  cent. 

To  produce  a  remunerative  crop  of  oats  after  rye  is 
only  possible  when  the  root-surface  of  the  oat  plant 
exceeds  that  of  the  rye  in  the  proportion  of  2 -23  to  1. 


168  FAKM-YAKD   MANURE. 

Oat  crops  will  therefore  exhaust  the  soil  the  most 
speedily  ;  after  12f  years  the  harvest  will  sink  to  three- 
fourths  of  the  original  amount. 

JSTone  of  the  causes  tending  to  diminish  or  increase 
the  crops  have  any  influence  on  this  law  of  exhaustion 
of  the  soil  by  cultivation.  Whenever  the  stock  of  nu- 
triment has  been  lowered  to  a  certain  point,  the  ground 
ceases  to  be  productive,  in  an  agricultural  sense,  for 
cultivated  plants. 

For  every  cultivated  plant  such  a  law  exists.  This 
state  of  exhaustion  will  inevitably  take  place,  even 
though  only  a  single  one  of  the  various  mineral  con- 
stituents required  for  the  nutrition  of  the  plants  has 
been  withdrawn  from  the  soil  by  a  succession  of  crops  ; 
for  the  one  constituent  which  fails  or  is  deficient  ren- 
ders all  the  rest  ineffective.  With  each  crop,  each 
plant,  or  portion  of  a  plant,  taken  away  from  a  field, 
the  soil  loses  part  of  the  conditions  of  its  fertility,  that 
is,  after  a  course  of  years  of  cultivation  it  loses  the 
power  of  again  producing  this  crop,  plant,  or  part  of  a 
plant.  A  thousand  grains  of  corn  require  from  the  soil 
a  thousand  times  as  much  phosphoric  acid  as  one 
grain. ;  and  a  thousand  straws  demand  a  thousand 
times  as  much  silicic  acid  as  one  straw.  When,  there- 
fore, the  soil  is  deficient  in  the  thousandth  part  of 
phosphoric  or  silicic  acid,  the  thousandth  grain  or 
the  thousandth  straw  will  not  be  formed.  If  a  single 
stalk  of  corn  is  taken  away  from  a  field,  the  conse- 
quence is  that  the  field  no  longer  produces  one  straw 
in  its  room. 

Hence  it  follows  that  a  hectare  of  ground,  contain- 
ing 25,000  kilogrammes  of  the  ash-constituents  of 
wheat,  uniformly  distributed,  and  presented  to  the 
roots  of  the  plants  in  a  perfectly  available  condition, 
can,  up  to  a  certain  point,  continue  to  give  in  succes- 
sion remunerative  crops  of  various  cereal  plants,  with- 
out receiving  any  restoration  of  the  mineral  constitu- 
ents taken  away  in  the  corn  and  straw,  provided  that 
the  uniform  mixture  of  the  soil  be  maintained  by  care- 
ful ploughing  and  other  suitable  means.  The  succes- 


UNEQUAL    DISTRIBUTION    OF   FOOD   IN    SOILS.  169 

sion  of  crops  is  determined  by  this  principle,  that  the 
second  plant  must  always  take  away  from  the  soil  less 
than  the  first,  or  possess  a  greater  number  of  roots,  or 
generally  a  larger  absorbent  root-surface.  After  the 
average  crop  of  the  first  year,  the  crops  would  go  on 
yearly  diminishing. 

The  farmer,  to  whom  uniform  average  harvests  are 
the  exception,  and  an  alternation  of  good  and  bad  crops 
dependent  upon  change  of  weather  is  the  rule,  would 
hardly  notice  this  constant  diminution,  even  supposing 
his  field  to  be  actually  in  that  favourable  chemical  and 
physical  condition  which  would  enable  him  to  cultivate 
wheat,  rye,  and  oats  for  seventy  years  in  succession, 
without  restoring  any  of  the  mineral  constituents  re- 
moved from  the  soil.  Good  crops  approaching  the 
average  in  favourable  years,  would  alternate  with  defi- 
cient crops  in  bad  seasons ;  but  the  proportion  of  un- 
favourable to  favourable  returns  would  go  on  in- 


creasing. 


Most  of  the  land  under  cultivation  in  Europe  is  not 
in  the  physical  condition  assumed  in  the  case  of  the 
field  which  we  have  been  considering. 

In  most  fields  the  phosphoric  acid  required  by  the 
plants  is  not  all  distributed  in  an  effective  condition, 
and  accessible  to  the  roots ;  a  part  of  it  is  merely  dis- 
seminated through  the  soil  in  the  form  of  small  gran- 
iiles  of  apatite  (phosphate  of  lime)  ;  and  even  where  the 
soil  contains  altogether  a  quantity  more  than  sufficient, 
yet  in  some  parts  of  it  there  is  much  more  and  in 
others  less  than  the  plants  require. 

If  we  suppose  our  field  to  contain  25,000  kilo- 
grammes of  the  ash-constituents  of  wheat  equally  dis- 
tributed through  the  soil,  and  five,  ten,  or  more  thou- 
sand pounds  of  the  same  constituents,  unequally  dis- 
tributed, the  phosphoric  acid  as  apatite,  the  silicic  acid 
and  potash  as  decomposable  silicates ;  and,  further,  if 
every  two  years  a  certain  quantity  of  this  second  por- 
tion of  food  elements  becomes,  in  the  manner  stated, 
soluble  and  distributable,  so  that  the  roots  of  plants  in 
all  parts  of  the  arable  soil  could  find  as  much  of  these 

8 


170  FARM-YAKD    MANURE. 

nutritive  substances  as  in  the  preceding  years  of  culti- 
vation— sufficient,  therefore,  for  an  average  crop ;  we 
should,  in  that  case,  be  able  to  obtain  full  average 
crops  for  a  number  of  years  by  always  letting  a  year 
of  fallow  intervene  after  a  year  of  cultivation.  Instead 
of  thirty  progressively  decreasing  crops,  we  should  in 
that  case  reap  thirty  full  average  crops  in  sixty  years, 
if  the  excess  of  mineral  matter  in  the  soil  were  suffi- 
ciently^ large  to  replace  everywhere  the  phosphoric 
acid,  silicic  acid,  and  potash  taken  away  in  each  year 
of  crops.  After  the  exhaustion  of  this  excess  of  min- 
eral matter,  the  period  of  diminishing  crops  would  com- 
mence for  our  field,  and  the  interposition  of  fallow 
years  would,  after  this,  no  longer  exercise  the  least  in- 
fluence on  the  production  of  larger  crops. 

If  the  excess  of  phosphoric  acid,  silicic  acid,  and 
potash,  which  we  have  assumed  in  the  case  under  con- 
sideration, were  not  unequally  but  uniformly  distrib- 
uted, and  everywhere  perfectly  accessible  and  available 
to  the  roots  of  the  plants,  our  field  would  be  able  to 
yield  thirty  full  average  crops  in  thirty  successive 
years,  without  the  intervention  of  a  season  of  fallow. 

Let  us  return  to  our  field,  which  we  have  assumed 
to  contain  25,000  kilogrammes  of  the  ash-constituents 
of  wheat,  equally  distributed  through  the  soil,  and  in  a 
suitable  state  for  absorption  by  the  roots.  Suppose  we 
were  to  cultivate  wheat  upon  it  year  after  year,  but  in- 
stead of  removing  the  entire  crop  we  were  merely  to 
cut  off  the  -ears,  leaving  the  strawr  on  the  ground  and 
immediately  ploughing  it  in  ;  the  loss  sustained  by  the 
field  would,  in  this  case,  be  less  than  before,  as  all  the 
constituents  of  the  straw  and  the  leaves  would  be  left 
in  the  field,  the  mineral  constituents  of  the  grain  alone 
having  been  removed. 

The  straw  and  leaves  contain,  among  their  constitu- 
ent elements,  the  same  mineral  substances  as  the  grain, 
only  in  different  proportions.  If  the  total  quantity  of 
phosphoric  acid  conveyed  away  in  the  straw  and  corn 
be  designated  by  the  number  3,  the  loss  will  be  only  2, 
if  the  straw  is  left  in  the  ground.  The  decrease  of 


RETARDATION   OF   THE   PERIOD   OF   EXHAUSTION.       171 

produce  from  the  field,  in  the  following  year,  is  always 
in  proportion  to  the  loss  of  mineral  substances  occa- 
sioned by  the  preceding  crop.  The  next  produce  of 
train  will  be  a  little  larger  than  it  would  have  been 
ad  the  straw  not  been  left  in  the  ground  ;  the  produce 
of  straw  will  be  nearly  the  same  as  in  the  preceding 
year,  because  the  conditions  for  the  formation  of  straw 
have  been  but  slightly  altered. 

Thus,  then,  by  taking  away  from  the  ground  less 
than  formerly,  we  increase  the  number  of  remunerative 
crops,  or  the  sum  total  of  grain  produced  in  the  whole 
series  of  corn  harvests.  Some  of  the  straw-constituents 
are  converted  into  corn-constituents,  and  are  now  re- 
moved from  the  field  in  the  latter  form.  The  period 
of  final  exhaustion,  though  sure  to  come  in  the  end, 
will,  under  these  circumstances,  occur  later.  The  con- 
ditions for  the  production  of  grain  go  on  continually 
decreasing,  because  the  substances  removed  in  the  corn 
are  not  replaced. 

It  would  make  no  difference  in  this  respect,  if  the 
straw  were  cut  and  carted  about  the  field,  or  used  as 
litter  for  cattle  and  then  ploughed  in  ;  the  supply  thus 
bestowed  upon  the  field,  having  been  originally  taken 
from  the  field,  cannot  enrich  it. 

Considering  that  the  combustible  elements  of  the 
straw  are  not  supplied  by  the  soil,  it  is  clear  that  in 
leaving  the  straw  in  the  ground  we  leave  nothing  more 
than  the  ash-constituents  of  the  straw.  The  field  re- 
mained somewhat  more  fruitful  than  before,  because  a 
little  less  had  been  taken  away. 

If  the  corn  or  its  ash-constituents  were  ploughed  in 
with  the  straw,  or  if,  instead  of  it,  a  corresponding 
quantity  of  some  other  seed  containing  the  same  ash- 
constituents  as  wheat,  e.  g.  ground  rape-cake,  that  is, 
rape-seed  freed  from  the  fatty  oil,  were  given  in  proper 
proportion  to  the  ground,  its  composition  would  remain 
the  same  as  before :  the  next  year's  crop  would  equal 
that  of  the  preceding  year.  If  after  every  harvest  the 
straw  is  always  in  this  manner  returned  to  the  field, 
the  further  consequence  will  be  an  inequality  in  the 


172  FAEM-YAED   MANUEE. 

composition  of  the  effective  constituents  in  the  arable 
soil. 

We  have  supposed  onr  field  to  contain  the  ash-con- 
tituents  of  the  entire  wheat  plant  in  proper  proportion 
for  the  formation  of  straw,  leaves,  and  grain.  By  leav- 
ing the  straw-constituents  in  the  ground  while  continu- 
ally removing  the  grain-constituents,  the  former  will 
accumulate  and  grow  out  of  due  proportion  to  the 
remainder  of  the  grain-constituents  still  contained  in 
the  field.  The  field  retains  its  fertility  for  straw,  but 
the  conditions  required  for  the  production  of  grain  are 
diminished. 

The  consequence  of  this  disproportion  is  an  unequal 
developement  of  the  entire  plant.  As  long  as  the  soil 
contained  and  supplied  the  right  proportion  of  ash-con- 
stituents needful  for  the  uniform  growth  of  all  parts  of 
the  plant,  so  long  the  quality  of  the  seed  and  the  ratio 
between  straw  and  corn  in  the  diminishing  crops  re- 
mained constant  and  unaltered.  But,  in  proportion  as 
the  conditions  for  the  production  of  leaves  and  straw 
became  more  favourable,  the  quality  of  the  grain  dete- 
riorated with  its  decreasing  quantity.  The  distinctive 
mark  of  this  inequality  in  the  soil,  resulting  from  cul- 
tivation, is  a  decrease  in  the  weight  of  the  bushel  of 
corn  reaped  from  the  field.  At  first  a  certain  quantity 
of  the  constituents  restored  to  the  soil  in  the  straw 
(phosphoric  acid,  potash,  magnesia),  was  expended  in 
the  formation  of  grain ;  but  afterwards  the  case  is  re- 
versed, and  the  grain-constituents  (phosphoric  acid, 
potash,  magnesia)  are  drawn  upon  for  the  production 
of  straw.  The  condition  of  a  field  is  conceivable  where 
by  reason  of  inequality  in  the  relative  conditions  for 
producing  straw  and  grain,  under  temperature  and 
moisture  favourable  for  the  formation  of  leaves,  a 
cereal  plant  may  yield  an  enormous  crop  of  straw, 
with  empty  ears. 

The  farmer,  in  cultivating  his  plants,  can  act  upon 
the  direction  of  the  vegetative  force  only  through  the 
soil,  i.  e.  by  supplying  his  field  with  nutritive  sub- 
stances, in  the  right  proportions.  For  the  production 


EXHAUSTION   OF  A   WHEAT   SOIL.  173 

of  the  largest  crop  of  grain,  the  soil  must  contain  a 
preponderating  quantity  of  the  nutritive  substances 
necessary  for  the  formation  of  seed.  For  leafy  plants, 
turnips,  and  tuberous  plants,  the  proportion  is  reversed. 

It  is  therefore  evident,  that  if  on  our  field  contain- 
ing 25,000  kilogrammes  of  the  ash-constituents  of  the 
wheat-plant,  we  cultivate  potatoes  and  clover,  and  take 
away  from  the  field  the  entire  crop  of  tubers  and  clo- 
ver, we  remove  from  the  ground,  in  these  two  products, 
as  much  phosphoric  acid  and  three  times  as  much  pot- 
ash as  in  three  wheat  crops. '  It  is  certain  that  the  ab- 
straction of  these  important  mineral  constituents  from 
the  ground,  by  the  cultivation  of  another  plant,  must 
greatly  affect  the  fertility  of  the  soil  for  wheat ;  the 
crops  of  wheat  diminish  in  amount  and  in  number. 

But  if,  instead  of  this,  we  were  to  cultivate  on  our 
field  alternately,  wheat  one  year,  potatoes  the  next, 
leaving  the  entire  potato  crop,  tubers  included,  and  the 
wheat  straw  on  the  ground  to  be  ploughed  in,  and  if 
this  alternation  of  crops  were  continued  for  sixty  years, 
the  crop  of  corn  which  the  field  was  originally  capable 
of  yielding  would  not  in  the  slightest  degree  be  altered 
or  increased.  The  field  would  gain  nothing  by  the 
cultivation  of  potatoes ;  and  would  lose  nothing,  be- 
cause the  whole  crop  was  left  in  the  soil.  When  by 
taking  corn  crops  from  the  field,  the  store  of  mineral 
constituents  had  been  reduced  to  three-fourths  of  the 
original  quantity,  the  field  would  cease  to  furnish  re- 
munerative crops,  supposing  that  three-fourths  of  an 
average  har7est  leave  no  margin  of  profit  for  the  far- 
mer. The  same  results  would  follow,  if  instead  of  po- 
tatoes we  interpose  clover,  and  constantly  ploughed  it 
in.  We  have  assumed  the  field  to  be  in  the  best  phys- 
ical condition,  which  therefore  could  not  be  improved 
by  the  incorporation  of  the  organic  substances  of  the 
clover  and  the  potatoes.  Even  if  we  were  to  take  the 
potatoes  from  the  field,  to  mow  down  and  dry  the  clo- 
ver, giving  both  to  cattle  in  the  farm-yard  or  making 
any  other  use  of  them,  and  then  to  bring  all  back  to 
the  field  and  plough  them  in,  so  as  to  restore  to  the 


174:  FARM-YAKD   MANURE. 

soil  all  the  mineral  constituents  contained  in  both  crops, 
yet  by  all  these  operations  the  field  would  not  produce, 
in  thirty,  sixty,  or  seventy  years,  a  single  grain  of  corn 
more  than  without  this  alternation.  The  conditions 
required  for  the  production  of  grain  are  not  improved 
in  the  field  during  the  whole  of  this  period,  and  the 
causes  of  decrease  in  the  crops  remain  the  same. 

The  ploughing  in  of  the  potatoes  and  the  clover 
could  have  a  beneficial  effect  upon  those  fields  only 
which  have  an  inferior  physical  condition,  or  in  which 
the  mineral  constituents  are  unequally  distributed,  or 
are  partially  inaccessible  to  the  roots  of  plants.  But 
this  effect  is  like  that  of  green  manuring,  or  of  one  or 
more  years  of  fallow. 

By  the  incorporation  of  the  clover  and  the  organic 
constituents  with  the  soil,  its  store  of  decaying  sub- 
stances and  nitrogen  increased  year  by  year.  All  that 
these  plants  received  from  the  atmosphere  remained  in 
the  ground  ;  but  the  increase  of  these  otherwise  so  use- 
ful substances  cannot  make  the  soil  produce  a  larger 
amount  of  grain  than  before ;  since  the  production  of 
grain  depends  upon  the  right  proportion  of  ash-constit- 
uents in  the  soil,  and  these,  so  far  from  being  increased, 
have  been  gradually  reduced  by  the  removal  of  the 
corn  crops.  The  augmentation  of  nitrogen  and  of  de- 
caying organic  substances  in  the  soil  might  possibly 
lead  to  an  increase  of  produce  for  a  number  of  years  ; 
but  the  period  when  this  field  will  cease  to  give  remu- 
nerative crops  will  in  that  case  come  all  the  sooner. 

If  we  take  three  wheat  fields,  and  cultivate  wheat 
upon  the  one,  potatoes  and  clover  upon  the  other  two  ; 
and  suppose  we  remove  the  corn  alone  from  the  wheat 
field  and  heap  upon  it  and  plough  in  all  the  crop  of 
clover  and  all  the  potato  tubers,  then  the  wheat  field 
will  be  more  fertile  than  before,  for  it  has  been  en- 
riched by  all  the  mineral  constituents  which  the  two 
other  fields  had  furnished  to  the  potatoes  and  the  clo- 
ver. It  has  received  three  times  as  much  phosphoric 
acid  and  twenty  times  as  much  potash  as  was  contained 
in  the  corn  crop  it  produced. 


GRADUAL  EXHAUSTION   OF  A  WHEAT   SOIL.  175 

This  wheat  field  will  now  be  able  to  produce  three 
full  corn  crops  in  three  successive  years,  because  the 
conditions  for  the  formation  of  straw  have  remained 
unaltered,  while  those  for  the  production  of  grain  have 
been  increased  three-fold.  If  the  farmer  by* this  method 
raises  as  much  corn  in  three  years  as  he  could  obtain 
from  the  same  fields  in  five  years  without  the  addition 
and  cooperation  of  the  constituents  contained  in  the  clo- 
ver and  the  potatoes,  it  is  clear  that  his  profit  has  been 
greater,  since  with  three  seed-corns  he  has  obtained  as 
good  a  harvest  as  in  the  other  case  with  five.  But 
what  the  wheat  field  has  gained  in  fertility,  the  other 
two  fields  have  lost ;  and  the  final  result  is,  that  at  less 
cost  of  cultivation,  and  with  more  profit  than  before, 
his  three  fields  are  brought  to  the  period  of  exhaustion 
which  inevitably  results  from  the  continued  removal  of 
the  mineral  constituents  in  the  crops  of  corn. 

The  last  case  which  we  have  to  consider  is  when 
the  farmer,  instead  of  growing  potatoes  and  clover,  cul- 
tivates turnips  and  lucerne,  which  by  their  long  pene- 
trating roots  extract  a  great  quantity  of  mineral  con- 
stituents from  the  subsoil,  to  which  the  roots  of  the 
cereals  very  seldom  penetrate.  "When  the  fields  have 
a  subsoil  favourable  to  the  growth  of  these  plants,  it  is 
as  though  the  arable  surface  soil  were  doubled.  If  the 
roots  of  these  plants  receive  the  half  of  their  mineral 
nutriment  from  the  subsoil,  and  the  other  half  from  the 
arable  surface  soil,  the  latter  will  lose  by  these  crops 
only  half  as  much  as  they  would,  if  all  the  mineral  con- 
stituents had  been  drawn  by  them  from  the  surface. 

Thus  the  subsoil,  considered  as  a  field  apart  from 
the  arable  soil,  gives  to  turnips  and  lucerne  a  certain 
quantity  of  mineral  constituents.  Now,  if  the  whole 
of  the  turnip  and  lucerne  crops  were  ploughed  in  dur- 
ing the  autumn  in  a  wheat  field  which  had  yielded  an 
average  crop  of  wheat,  so  that  the  field  should  receive 
back  more  than  it  had  lost  in  the  corn,  it  is  clear  that 
this  field  might  be  maintained  in  an  equable  state  of 
fertility,  at  the  expense  of  the  subsoil,  just  so  long  as 
the  latter  remained  productive  for  turnips  and  lucerne. 


176  FARM- YARD   MANURE. 

As,  however,  turnips  and  lucerne  require  for  their 
dev elopement  a  very  great  quantity  of  mineral  constitu- 
ents, the  subsoil  is  so  much  the  sooner  exhausted,  when 
it  contains  fewer  of  such  constituents.  Now  as  it  is 
not  actually  severed  from  the  arable  surface,  but  lies 
underneath,  it  can  scarcely  regain  any  of  all  the  con- 
stituents which  it  has  lost,  because  the  surface  soil  in- 
tercepts and  retains  the  portion  supplied.  Only  that 
part  of  the  potash,  ammonia,  phosphoric  acid,  and 
silicic  acid,  which  is  not  taken  up  and  fixed  by  the  sur- 
face soil,  can  reach  the  subsoil. 

It  is  therefore  possible,  by  the  cultivation  of  these 
deep-rooting  plants,  to  gain  an  abundant  supply  of  nu- 
tritive substances  for  all  plants  drawing  their  nutriment 
chiefly  from  the  arable  soil ;  but  this  supply  is  not  last- 
ing, and  in  a  comparatively  short  time  many  fields  will 
cease  to  bear  crops,  because  the  subsoil  is  exhausted, 
and  its  fertility  is  not  easily  restored. 

If  a  farmer  grows  upon  three  fields,  potatoes,  corn, 
and  vetches  or  clover,  alternately,  or  if  he  cultivates 
one  field  with  potatoes,  corn,  and  vetches  successively, 
selling  the  crops,  and  going  on  in  the  same  way  for 
many  years,  without  manuring,  any  one  can  foresee 
the  end  of  such  husbandry,  because  such  a  system  can- 
not possibly  last.  No  matter  what  plants  may  be 
selected,  what  variety  of  cereals,  tuberous  or  other 
plants,  or  in  what  rotation,  the  field  will  at  length  be 
reduced  to  such  a  state  that  the  cereals  will  yield  no 
more  than  the  seed  sown,  the  potatoes  will  give  no 
tubers,  and  the  vetches  or  clover  will  die  away  after 
barely  appearing  above  ground. 

From  these  facts  it  follows  indisputably,  that  there 
is  no  plant  which  spares  the  ground,  and  none  which 
enriches  it.  The  practical  farmer  is  taught  by  innu- 
merable instances  that  the  success  of  a  second  crop  de- 
pends upon  the  previous  one,  and  that  it  is  by  no 
means  a  matter  of  indifference,  in  what  order  he  culti- 
vates his  plants  ;  by  previously  cultivating  some  plant 
with  extensive  ramification  of  roots,  the  soil  is  made 
fitter  for  the  growth  of  a  succeeding  cereal,  which  will 


A   SECOND  CROP  DEPENDS   ON   THE   PRECEDING   ONE.      177 

now  thrive  better,  even  without  the  application  of  ma- 
nure (with  sparing  application),  and  yield  a  richer  crop. 
But  this  is  not  a  saving  of  manure  for  future  crops,  nor 
has  the  field  been  enriched  in  the  conditions  of  its  fer- 
tility. There  has  been  an  increase,  not  in  the  sum  of 
the  nutriment,  but  in  the  available  particles  of  that 
sum,  and  their  operation  has  been  hastened  in  point  of 
time. 

The  physical  and  chemical  condition  of  the  field 
was  improved  ;  but  the  store  of  chemical  elements  was 
reduced.  All  plants,  without  exception,  drain  the  soil, 
each  in  its  own  way,  and  exhaust  the  conditions  for 
their  reproduction. 

In  the  produce  of  his  field  the  farmer  actually  sells 
his  land ;  he  sells,  in  his  crops,  certain  elements  of  the 
atmosphere,  which  come  of  themselves  to  his  soil ;  and 
with  them  certain  constituents  of  the  ground,  which 
are  his  property,  and  which  have  served  to  form,  out 
of  the  atmospheric  elements,  the  body  of  the  plant, 
being  themselves  component  parts  of  that  body.  In 
alienating  the  crops  of  his  field,  he  robs  the  land  of  the 
conditions  required  for  their  reproduction.  Such  a 
system  of  husbandry  may  properly  be  called  a  system 
of  spoliation. 

The  constituents  of  the  soil  are  the  farmer's  capital ; 
the  atmospheric  nutritive  substances  are  the  interest  of 
his  capital ;  with  the  former  he  produces  the  latter. 
In  selling  the  produce,  he  alienates  part  of  his  capital 
and  the  interest ;  in  restoring  the  constituents  of  the 
soil  to  the  ground,  he  retains  his  capital. 

Common  sense  tells  us,  and  all  farmers  agree,  that 
clover,  turnips,  hay,  &c.,  cannot  be  sold  off  from  a 
farm  without  materially  damaging  the  productive 
power  of  the  land  for  corn. 

Everyone  willingly  admits,  that  the  removal  of  clo- 
ver is  prejudicial  to  the  cultivation  of  corn  ;  but  that 
the  removal  of  corn  should  injure  the  cultivation  of 
clover  is  to  most  farmers  an  inconceivable,  nay,  an  im- 
possible idea. 

Yet  the  natural  connection  and  mutual  relations 

8* 


178  FAKM-YARD   MANUKE. 

between  the  two  classes  of  plants  are  as  clear  as  day- 
light. The  ash-constituents  of  clover  and  corn  are  the 
conditions  for  the  formation  of  clover  and  corn,  and  are 
identical  as  far  as  the  elements  are  concerned. 

Clover,  just  like  corn,  requires  for  its  production  a 
certain  amount  of  phosphoric  acid,  potash,  lime,  and 
magnesia.  The  mineral  constituents  of  clover  are  the 
same  as  those  of  coru^plus  a  certain  excess  of  potash, 
lime,  and  sulphuric  acid.  The  clover  draws  these  con- 
stituents from  the  soil,  the  cereal  plants  may  be  repre- 
sented as  deriving  them  from  the  clover.  In  selling 
his  clover,  therefore,  the  farmer  takes  away  the  condi- 
tions for  the  production  of  corn,  and  there  remains  be- 
hind in  the  soil  less  nutriment  for  the  corn ;  if  he  sells 
his  corn,  he  takes  away  from  the  land  some  of  the  most 
indispensable  conditions  for  the  production  of  clover, 
hence  the  clover  crop  fails  in  the  subsequent  year. 

The  peasant  knows  the  operation  of  these  fodder- 
plants,  and  expresses  his  views  in  his  own  way  when 
he  says,  '  that,  as  a  matter  of  course,  a  man  must  not 
sell  his  manure,  without  which  no  permanent  cultiva- 
tion is  possible,  and  that  in  selling  the  fodder-plants,  a 
man  sells  his  manure.'  But  that  in  selling  his  corn,  a 
farmer  is  still  parting  with  his  manure,  does  not  seem 
to  be  understood  by  many  even  of  the  most  enlightened 
agriculturists.  Farm-yard  manure  contains  all  the  min- 
eral constituents  of  fodder ;  and  these  consist  of  the 
constituents  of  corn,  plus  a  certain  quantity  of  potash, 
lime,  and  sulphuric  acid.  It  is  quite  evident,  that  as 
the  whole  dung-heap  consists  of  parts,  not  one  of  those 
parts  should  be  alienated ;  and  if  it  were  possible,  by 
any  means,  to  separate  the  corn-constituents  from  the 
rest,  they  would  possess  the  greatest  value  to  the  far- 
mer, because  upon  them  the  cultivation  of  the  corn 
depends.  But  this  separation  actually  takes  place  in 
the  growth  of  corn,  as  the  mineral  constituents  of  the 
manure  become  the  constituents  of  the  corn  ;  hence  in 
selling  the  corn,  the  farmer  alienates  a  portion,  and 
indeed  the  most  efficient  portion,  of  his  manure. 

Two  dung-heaps,  looking  quite  alike,  and  apparently 


CORN    SOLD   IS    MANURE    LOST.  179 

of  the  same  quality,  may  yet  have  a  very  dissimilar 
value  for  the  cultivation  of  corn.  If  in  one  heap  the 
ash-constituents  of  corn  are  twice  as  many  as  in  the 
other,  the  former  has  double  the  value  of  the  other. 
By  the  removal  of  the  mineral  constituents  of  the  corn, 
which  were  derived  from  the  manure,  the  efficacy  of 
the  manure  with  regard  to  future  corn  crops  is  con- 
stantly diminished. 

From  whatever  point  of  view,  therefore,  the  aliena- 
tion of  corn  or  other  field  produce  may  be  regarded,  the 
farmer  who  does  not  replace  the  mineral  constituents 
taken  away  in  the  crops,  will  find  that  the  inevitable 
result  is  exhaustion  of  the  soil.  Continued  removal  of 
the  corn  crops  makes  the  ground  unproductive  for  clo- 
ver, or  deprives  the  manure  of  its  efficacy. 

In  our  exhausted  fields  the  roots  of  cereals  no  longer 
find,  in  the  upper  layers  of  the  soil,  sufficient  nutriment 
for  the  production  of  a  full  crop  :  the  farmer,  therefore, 
grows  on  these  fields  clover,  turnips,  and  other  plants 
of  the  kind,  which,  with  their  wide-spreading  and  deep 
roots,  penetrate  in  all  directions  through  the  soil,  open 
up  the  ground  by  their  large  root-surface,  and  appro- 
priate the  constituents  which  are  needed  by  cereals  for 
the  formation  of  seed.  In  the  residue  of  these  plants, 
in  the  constituents  of  the  stalks,  the  roots  and  the 
tubes,  which  the  farmer  puts  upon  the  arable  surface  in 
the  form  of  manure,  he  restores  to  the  land,  in  a  con- 
centrated form,  the  corn-constituents  for  one  or  several 
full  crops  :  what  was  below  and  scattered,  is  now  above. 
The  clover  and  the  fodder-plants  did  not  engender  the 
conditions  of  richer  corn-crops,  any  more  than  rag- 
gatherers  produce  the  conditions  for  paper-making : 
they  are  mere  collectors. 

From  the  foregoing  remarks  it  is  evident  that  the 
cultivation  of  plants  exhausts  the  fertile  soil,  and  ren- 
ders it  unfruitful.  In  selling  the  produce  of  his  fields, 
which  serves  as  food  for  man  and  beast,  the  farmer  re- 
moves a  portion  of  his  soil,  and  indeed  the  constituents 
most  efficient  for  the  production  of  future  crops.  In 
course  of  time,  the  fertility  of  his  fields  will  decrease, 


180  FAKM-YARD   MANURE. 

no  matter  what  plants  he  cultivates,  or  what  order  of 
rotation  he  may  adopt.  The  removal  of  his  crops  is 
nothing  else  than  robbing  the  ground  of  the  conditions 
for  future  harvests. 

A  field  is  not  exhausted  for  corn,  clover,  tobacco,  or 
turnips,  so  long  as  it  yields  remunerative  crops,  with- 
out needing  the  replacement  of  those  mineral  constitu- 
ents which  have  been  carried  away.  It  is  exhausted 
from  the  time  that  the  hand  of  man  is  needed  to  restore 
the  failing  conditions  of  its  fertility.  In  this  sense 
most  of  our  cultivated  fields  are  exhausted. 

The  life  of  men,  animals,  and  plants  is  most  inti- 
mately connected  with  the  restoration  of  all  those  con- 
ditions which  cause  the  vital  process  to  go  on.  The 
soil,  by  its  constituents,  takes  part  in  the  life  of  the 
plant ;  its  permanent  fertility  is  inconceivable  and  im- 
possible, without  the  replacement  of  those  conditions 
which  have  made  it  productive. 

The  mightiest  river  which  sets  in  motion  thousands 
of  mills  and  machines  must  fail,  if  the  streams  and 
brooks  supplying  its  waters  run  dry ;  so,  too,  the 
streams  and  brooks  wrill  run  dry  if  the  many  little 
drops  of  which  they  consist  fail  to  return  in  the  form 
of  rain  to  the  place  whence  their  sources  spring. 

A  field  which,  by  the  successive  cultivation  of 
different  plants,  has  lost  its  fertility,  may  recover  the 
power  of  yielding  a  new  series  of  crops  of  the  same 
plants,  by  the  application  of  manure. 

What  is  manure,  and  whence  comes  it  ?  All  ma- 
nure comes  from  the  farmer's  fields :  it  consists  of 
straw,  which  has  served  as  litter  ;  of  remains  of  plants, 
of  the  liquid  and  solid  excrements  of  men  and  animals. 
The  excrements  are  derived  from  food. 

In  his  daily  bread,  man  consumes  the  ash-constitu- 
ents of  the  grain  from  the  flour  of  which  bread  is 
made :  in  meat  he  consumes  the  ash-constituents  of 
flesh. 

The  flesh  of  herbivorous  animals,  and  its  ash-con- 
stituents, are  derived  from  plants ;  these  ash-constitu- 
ents are  identical  with  those  of  the  seeds  in  leguminous 


MUTUAL   RELATION    OF   PLANTS    AND   ANIMALS.        181 

plants.  Hence  if  an  entire  animal  is  burnt  to  ashes, 
the  residue  will  differ  little  from  the  ashes  of  beans, 
lentils,  and  peas. 

In  bread  and  flesh,  therefore,  man  consumes  the 
ash-constituents  of  seed,  or  of  seed-constituents  which 
the  farmer  has  obtained  from  his  fields  in  the  form  of 
flesh. 

Of  the  large  amount  of  mineral  substances  which 
man  consumes  in  his  food  during  a  lifetime,  but  a  small 
fraction  remains  in  his  body.  The  body  of  an  adult 
does  not  increase  in  weight  from  day  to  day,  which 
proves  that  all  the  constituents  of  his  food  must  com- 
pletely pass  out  again  from  his  system. 

Chemical  analysis  demonstrates  that  the  excrements 
of  man  contain  the  ash-constituents  of  bread  and  flesh 
very  nearly  in  the  same  quantity  as  they  exist  in  the 
food,  which  in  the  body  undergoes  a  change  similar  to 
that  which  would  take  place  in  a  furnace. 

The  urine  contains  the  soluble,  the  solid  excrements 
the  insoluble  ash-constituents  of  food  :  the  stinking  sub- 
stances are  the  smoke  and  soot  of  an  imperfect  combus- 
tion. "With  these  are  mixed  up  the  undigested  and  the 
indigestible  remains  of  food. 

The  dung  of  swine  fed  on  potatoes  contains  the  ash- 
constituents  of  the  potato ;  that  of  the  horse,  the  ash- 
constituents  of  hay  and  oats ;  that  of  cattle,  the  ashes 
of  turnips,  clover,  and  other  plants  which  have  served 
them  as  food.  Farm-yard  manure  comprises  a  mixture 
of  all  these  excrements. 

That  farm-yard  manure  will  completely  restore  the 
fertility  of  a  field  exhausted  by  cultivation  is  a  fact 
fully  established  by  the  experience  of  a  thousand  years. 

Farm-yard  manure  supplies  to  the  field  a  certain 
quantity  ^of  organic,  i.  e.  combustible  substances,  to- 
gether with  the  ash-constituents  of  the  food  consumed. 
We  must  now  consider  what  part  is  taken,  in  the 
restoration  of  fertility,  by  the  combustible  and  incom- 
bustible constituents  of  the  manure. 

The  most  superficial  examination  of  a  cultivated 
field  shows  that  all  the  combustible  constituents  of  the 


182  FARM-YAKD   MANUKE. 

plants  grown  upon  it  are  derived  from  the  air  and  not 
from  the  soil.  If  the  carbon  even  of  a  portion  of  the 
vegetable  matter  in  the  crop  were  derived  from  the 
soil,  it  is  quite  clear,  that  if  the  ground  contained  a 
certain  amount  of  carbon  before  the  harvest,  this 
amount  must  be  smaller  after  every  harvest.  A  soil 
deficient  in  organic  matter  must  necessarily  be  less 
productive  than  a  soil  abounding  in  it. 

Now,  experience  proves  that  a  field  in  constant  cul- 
tivation does  not,  therefore,  become  poorer  in  organic 
or  combustible  substances.  The  soil  of  a  meadow 
which  in  ten  years  has  yielded  a  thousand  cwt.  of  hay 
per  hectare,  is  found  to  be,  at  the  end  of  those  ten 
years,  not  poorer  in  organic  substances,  but  richer  than 
before.  A  clover-field  after  a  crop  retains  in  the  roots 
left  in  the  ground  more  organic  substances,  more  nitro- 
gen, than  it  originally  possessed ;  yet  after  a  number 
of  years  it  becomes  unproductive  for  clover,  and  no 
longer  gives  remunerative  returns  of  that  crop. 

A  field  of  wheat,  or  potatoes,  is  not  poorer  in  or- 
ganic substances  after  harvest,  than  before.  ,As  a  gen- 
eral rule,  cultivation  increases  the  store  of  combustible 
constituents  in  the  ground,  while  its  fertility,  however, 
steadily  diminishes.  After  a  consecutive  series  of  re- 
munerative crops  of  corn,  turnips,  and  clover,  these 
plants  will  thrive  no  longer  in  the  same  field. 

Since,  then,  the  presence  of  decaying  organic  re- 
mains in  the  soil  does  not,  in  the  slightest  degree,  pre- 
vent or  arrest  its  exhaustion  by  cultivation  ;  it  is  im- 
possible that  an  increase  of  those  substances  can  restore 
the  lost  capacity  of  a  field  for  production.  In  fact, 
when  a  field  is  completely  exhausted,  neither  boiled 
saw-dust  nor  salts  of  ammonia,  nor  both  combined,  will 
impart  the  power  of  yielding  the  same  series  of  crops  a 
second  and  third  time.  When  these  substances  im- 
prove the  physical  condition  of  the  ground,  they  exert 
a  favourable  influence  upon  the  produce  ;  but,  after  all, 
their  ultimate  effect  is  to  accelerate  and  complete  the 
exhaustion  of  the  soil. 

But  farm-yard  manure  thoroughly  restores  to  the 


MINERAL   MATTERS   RESTORED   BY    MAN.  183 

soil  the  power  of  producing  the  same  succession  of 
crops  a  second,  a  third,  and  a  hundredth  time :  where 
it  is  applied  in  proper  quantities  it  will  fully  cure  the 
state  of  exhaustion,  and  often  make  a  field  more  fertile 
than  it  ever  was  before. 

The  restoration  of  fertility  by  farm-yard  manure 
cannot  be  attributed  to  the  mixture  of  combustible 
materials  (salts  of  ammonia  and  the  substance  of  decay- 
ing saw-dust) :  for  if  these  had  a  favourable  effect,  it 
must  have  been  of  a  subordinate  kind.  The  action  of 
farm-yard  manure  most  undoubtedly  depends  upon  the 
incombustible  ash-constituents  of  the  plants  which  it 
contains. 

In  farm-yard  manure  the  field  actually  receives  a 
certain  quantity  of  all  the  mineral  ingredients  which 
have  been  removed  in  the  crops.  The  decline  of  fertil- 
ity was  in  proportion  to  the  removal  of  mineral  con- 
stituents ;  the  renewal  of  productiveness  is  in  propor- 
tion to  their  restoration. 

The  incombustible  elements  of  cultivated  plants  do 
not  of  themselves  return  to  the  soil,  as  the  combustible 
elements  return  to  the  atmosphere  from  which  they 
spring.  The  hand  of  man  alone  restores  to  the  ground 
the  conditions  of  the  life  of  plants :  in  farm-yard  ma- 
nure wherein  they  are  contained,  the  farmer,  following 
a  natural  law,  restores  the  lost  power  of  production. 


CHAPTEB  Y. 

THE   SYSTEM   OF  FARM-YARD   MANURING. 

Questions  to  be  solved— Experiments  of  Kenning,  their  significance— Produce  of 
unmanured  fields — Influence  of  preceding  crops,  of  the  situation,  and  climatic 
conditions,  on  the  produce— Each  field  possesses  its  own  power  of  production 
— Large  crops,  their  dependence  and  continuation— Closeness  of  the  food  of 
plants,  what  is  meant  thereby— The  closeness  of  the  particles  of  food  in  the 
soil  is  in  proportion  to  the  produce— Produce  of  corn  and  straw  influenced  by 
the  relations  of  the  assimilated  food  and  by  the  conditions  of  growth  ;  action 
of  food  supplied  in  manures— Potatoes,  oats,  and  clover  crops  of  the  Saxon 
fields  ,  conclusions  drawn  from  them  as  to  the  condition  of  the  fields— Produce 
of  these  fields  from  farm-yard  manure ;  the  increase  of  produce  cannot  be  cal- 
culated from  the  amount  of  manure  used— Restoration  of  the  power  of  produc- 
tion of  exhausted  fields  by  the  increase  of  the  necessary  elements  of  food  pre- 
sent in  the  soil  in  minimum  amount ;  advantageous  use  of  farm-yard  manure 
in  this  respect ;  explanation  of  the  result-  Action  of  manure  as  compared  with 
quantity  used  •  experiments — Rational  system  of  cultivation — Depth  to  which 
the  food  of  plants  penetrates  is  dependent  on  the  power  of  absorption  of  the 
eoil  ;  the  Saxon  fields  considered  in  this  respect ;  the  power  of  absorption  con- 
sidered in  manuring— Change  produced  in  the  composition  of  the  soil  by  tho 
system  of  farm-yard  manuring;  the  different  stages  of  this  system,  the  final 
result — Examples  of  these  stages  in  the  Saxon  experimental  fields — Cause  of 
the  growth  of  weeds  ;  remedies— The  history  of  husbandry,  what  is  taught  by 
it — Present  condition  of  European  husbandry — Present  production  of  the  land 
compared  with  the  earlier  ,  conclusions — Continuation  of  production  regulated 
by  a  natural  law — Law  of  restoration  ;  defective  practice  of  it — Agriculture  in 
the  time  of  Charlemagne — Agriculture  in  the  Palatinate — Corn  fields  in  the 
valleys  of  the  Nile  and  Ganges  ;  nature  provides  in  them  for  the  restoration  of 
food  of  plants — Practical  agriculture  and  thelaw  of  restoration — The  statistical 
returns  of  average  crops  afford  an  explanation  of  the  condition  of  corn  fields. 

THE  general  observations  in  the  preceding  chapters 
on  the  mutual  relations  between  the  soil  and  plants, 
as  also  on  the  sources  and  nature  of  farm-yard  manure, 
will,  I  hope,  enable  the  reader  to  enter  upon  a  thorough 
investigation  of  all  those  phenomena  which  are  pre- 
sented^by  the  practice  of  farm-yard  manuring.  We 
have  to  consider  how  farm-yard  manure  increases  the 
produce  of  a  field ;  on  which  constituents  of  the 
manure  its  action  depends ;  what  quantity  of  farm-yard 
manure  can  be  obtained  from  a  field  ;  and  to  what  con- 


QUESTIONS    TO   BE   CONSIDERED.  185 

dition,  after  a  series  of  years,  a  field  can  be  restored  by 
farm-yard  manuring. 

It  will  be  understood  that  from  this  investigation 
we  exclude  all  those  effects  of  farm-yard  manure  which 
cannot  be  determined  by  measure  and  number ;  such, 
for  instance,  as  its  influence  upon  the  looseness  or  cohe- 
sion of  the  soil,  and  its  heating  action,  by  means  of  the 
warmth  resulting  from  the  decay  of  its  constituents  in 
the  ground. 

The  facts,  to  which  this  investigation  extends,  are 
derived  from  practical  experience ;  and  my  selection  of 
them  has  been  materially  facilitated  by  the  comprehen- 
sive series  of  experiments  made  in  the  year  1851,  at  the 
instance  of  DR.  KENNING,  Secretary-General  of  the 
Agricultural  Society  in  the  kingdom  of  Saxony,  by  a 
number  of  Saxon  agriculturists,  with  a  view  of  '  ascer- 
taining the  action  of  so-called  artificial  manures  under 
every  variety  of  condition,  for  the  purpose  of  more  gen- 
erally extending  their  application.'  These  experiments 
were  continued  to  the  year  1854,  every  series  embra- 
cing a  rotation  of  rye,  potatoes,  oats,  and  clover.  The 
farmers  were  requested  to  try  bone-dust,  rape-cake, 
meal,  guano,  and  farm-yard  manure,  each  on  a  Saxon 
acre  (  =  1*36  English  acre)  of  ground  compared  with 
an  unmanured  plot  of  the  same  size,  and  to  determine 
the  respective  crops  by  weight. 

Of  all  experiments  of  a  similar  nature  which  have 
been  made  in  the  course  of  several  centuries,  those 
which  are  expressly  stated  to  have  been  undertaken 
'without  a  direct  scientific  object'  are  of  the  highest 
scientific  importance,  not  only  for  their  very  compre- 
hensive character,  but  because  they  have  resulted  in 
fully  establishing  a  number  of  facts  which  will  for  all 
time  to  come  retain  their  validity  as  safe  bases  for 
scientific  conclusions.  Science  owes  the  deepest  grati- 
tude to  the  excellent  propound er  of  these  inquiries,  and 
to  the  worthy  men  who  so  zealously  performed  their 
task ;  the  only  thing  to  be  regretted  is,  that  the  experi- 
ments upon  unmanured  plots  were  not  carried  out  in 
all  cases. 


186 


THE    SYSTEM    OF   FARM-YARD    MANURING. 


It  is  evident  that  the  action  of  farm-yard  manure 
upon  a  field  can  be  properly  estimated  only  if  it  is 
known  beforehand  what  amount  of  produce  the  field 
will  give  without  any  manure  :  and  first  of  all  we  shall 
consider  the  crops  produced  on  five  fields  in  five  differ- 
ent parts  of  Saxony,  in  the  four-year  rotation  above 
mentioned. 


Crop. 

Unman  tired. 

Cunnersdorf. 

Maueegast 
mixture. 

Kotitz 
white  clover. 

Oberbobritzsck 
red  clover. 

Oberschona 
grass. 

1851. 

Rye 

Grain.  .  .  . 
Straw   .  .  . 

Ibs. 

1176 
2951 

Ibs. 

2238 
4582 

Ibs. 

1264 
3013 

Ibs. 

1453 
3015 

Ibs. 

708 
1524 

1852. 
Potatoes.  . 

16667 

16896 

18577 

9751 

11095 

1853. 
Oats 
Grain.  .  .  . 
Straw  .  .  . 

2019 
2563 

1289 
1840 

1339 
1357 

1528 
1812 

1082 
1714 

1854. 
Clover-hay 

9144 

5583 

1095 

911 

— 

These  results  lead  to  the  following  considerations. 

The  term  unmanured,  as  applied  to  these  fields,  is 
meant  to  designate  the  condition  in  which  they  were 
left  at  the  end  of  a  rotation  by  a  succession  of  crops. 

These  fields  had  been  manured  at  the  beginning  of 
the  rotation ;  and  had  they  been  manured  afresh,  they 
would  have  produced  the  same  crops  as  before.  In  the 
crops  yielded  by  them  in  the  manured  state,  the  con- 
stituents of  the  soil  and  those  of  the  manure  had  a  cer- 
tain definite  share ;  if  the  fields  had  not  been  manured, 
the  crops  would  have  been  smaller.  Now  if  we  at- 
tribute the  increased  produce  during  the  course  of  the 
rotation  to  the  supply  of  farm-yard  manure,  and  suppose 
that  the  constituents  of  the  farm-yard  manure  have 


THE    SOIL    AND   THE    PRODUCE.  1ST 

been  again  removed  in  tlie  crops,  which  is  not  true  in 
all  cases,  then  the  field,  at  the  end  of  the  rotation,  is  in 
the  same  state  in  which  it  was  at  the  commencement, 
before  it  had  been  manured.  Accordingly,  we  may 
assume,  without  great  risk  of  error,  that  the  produce  of 
different  crops,  which  a  plot  of  ground  will  yield  in  a 
new  rotation  without  manuring,  will  be  in  proportion 
to  the  store  of  nutritive  substances,  ready  for  assimila- 
tion, which  it  contains  in  its  natural  state.  Hence  from 
the  unequal  products  yielded  by  the  two  fields  in  that 
state,  we  may,  with  an  approximation  to  truth,  infer 
certain  inequalities  in  the  amount  of  food  or  in  the  con- 
dition of  the  fields. 

Of  course,  inferences  of  this  kind  are  admissible  only 
within  very  narrow  limits ;  for  when  we  compare  two 
fields  which  lie  in  the  same  or  in  different  districts,  we 
must  remember  that  in  each  case  various  factors  operate 
upon  the  products,  making  these  unequal,  even  though 
the  nature  of  the  soil  be  otherwise  identical. 

If,  for  instance,  two  fields,  both  unmanured,  are 
planted  with  one  and  the  same  cereal,  it  is  by  no  means 
a  matter  of  indifference,  as  regards  the  produce  of  corn 
and  straw,  what  crop  has  preceded  the  cereal.  If  the 
last  crop  in  the  preceding  rotation  was  clover  on  the 
one,  oats  on  the  other  field,  .the  results  will  vary,  even 
though  the  condition  of  the  soil  in  both  was  originally 
identical ;  and  the  produce  reaped,  in  that  case,  indi- 
cates merely  the  state  into  which  the  field  has  been 
brought  by  the  preceding  crop. 

In  hilly  districts,  a  northern  or  southern  aspect 
makes  a  difference  in  the  comparative  character  of  two 
fields  ;  so  too  does  the  height  above  the  sea,  on  which 
the  quantity  of  the  fall  of  rain  depends.  A  fall  of  rain 
received  at  a  more  favourable  time  by  one  field  than 
by  another  makes  a  difference  in  the  amount  of  pro- 
duce, even  though  the  condition  of  the  soil  be  the  same 
in  both  fields. 

Lastly,  in  judging,  in  the  manner  indicated,  of  the 
state  and  condition  of  a  field,  the  weather  during  the 
preceding  year  must  be  taken  into  account. 


188  THE    SYSTEM    OF   FARM-YARD    MANURING. 

The  crop  produced  by  a  field  in  a  year  is  always  the 
maximum  crop  which  it  can  yield  under  the  conditions 
given :  under  more  favourable  external  circumstances, 
that  is,  with  better  weather,  the  field  would  have  fur- 
nished a  greater  crop ;  under  more  unfavourable  circum- 
stances, a  smaller,  always  corresponding  to  the  condi- 
tion of  the  soil. 

By  the  production  of  larger  crops,  in  consequence 
of  favourable  weather,  the  field  loses  a  comparatively 
greater  amount  of  nutritive  substances,  and  the  sub- 
sequent harvests  show  a  decline ;  just  as,  on  the  other 
hand,  deficient  crops  will  act  upon  the  yield  of  subse- 
quent years,  as  a  fallow  year  with  half-manuVing  does, 
that  is,  the  crops  coming  after  bad  years  will  turn  out 
better,  even  in  ordinary  weather. 

The  relative  proportions  of  corn  and  straw,  in  a  crop 
of  cereals,  are  altered  by  a  continuance  of  dry  or  wet 
weather.  Permanent  wet,  combined  with  a  high  tem- 
perature, favours  the  development  of  leaves,  stalks  and 
roots ;  and  as  the  plant  goes  on  growing,  the  materials 
intended  for  the  production  of  seed  are  used  for  the 
formation  of  new  shoots,  and  thus  the  seed  crop  is 
diminished. 

Continuous  drought,  before  or  during  sprouting 
time,  produces  the  opposite  effect ;  the  store  of  forma- 
tive matter  accumulated  in  the  roots  is  used  in  far 
greater  proportion  for  the  production  of  seed,  and  the 
relation  of  straw  to  corn  is  smaller  than  it  would  be  in 
ordinary  weather. 

When  all  these  circumstances  are  taken  into  account, 
the  consideration  of  the  produce  obtained  from  un- 
manured  fields  in  the  Saxon  experiments  will  leave  only 
a  few  general  points  for  further  investigation. 

The  tabular  statement  of  the  result  shows  that  each 
field  has  a  power  of  production  peculiar  to  itself,  and 
that  no  two  of  them  have  produced  the  same  amount 
of  rye  corn  and  straw,  or  potatoes,  or  oats  and  straw,  or 
clover. 

If  we  compare  the  numberless  manuring  experi- 
ments of  the  last  few  years,  in  which  the  crops  obtained 


THE   PRODUCTIVE    POWER   OF   LAND    VARIES.  189 

I 

from  unmanured  plots  were  likewise  taken  into  ac- 
count, we  see  that  this  is  a  general  rule  admitting  of  no 
exception  :  no  two  fields  have  exactly  the  same  produc- 
tive power ;  nay,  there  are  not  even  two  plots  in  the 
same  field  which  are  identical  in  this  respect.  We 
need  only  look  at  a  turnip  field  to  see  at  once  that 
every  turnip  differs  in  size  and  weight  from  the  one 
growing  next  to  it.  This  fact  is  so  universally  known 
and  admitted,  that  in  all  countries  where  the  land  is 
taxed,  the  amount  of  the  impost  is  assessed  according 
to  the  quality  of  the  soil,  in  some  countries  in  eight 
classes,  in  others  in  twelve  or  sixteen. 

Since,  then,  no  two  fields  are  alike  in  productive 
power,  and  every  field  must  necessarily  contain  the  con- 
ditions required  for  the  production  of  the  crops  which 
it  yields,  it  is  clear  that  the  conditions  for  the  produc- 
tion of  corn  and  straw,  or  of  turnips  and  potatoes,  or  of 
clover  or  any  other  plant,  are  in  no  two  fields  alike  :  in 
one  field  the  conditions  for  the  production  of  straw  pre- 
ponderate over  those  for  the  production  of  grain, 
another  is  better  suited  for  the  growth  of  clover,  and 
so  on. 

These  conditions,  according  to  their  very^  nature, 
differ  in  quantity  and  quality.  By  conditions  which 
can  be  weighed  and  measured,  we  of  course  mean  no 
other  than  nutritive  substances. 

The  crops  reaped  from  a  field  afford  no  indication 
of  the  quantity  of  nutritive  substances  in  the  ground. 
Consequently,  the  fact  that  the  field  at  Mausegast  gave 
twice  as  much  corn  and  one-third  more  straw  than  the 
one  at' Cunnersdorf,  cannot  lead  to  the  inference  that 
the  former  was  upon  the  whole  richer  in  these  propor- 
tions in  the  conditions  for  the  production  of  corn  and 
straw ;  for  we  see  that  the  Cunnersdorf  field  gave  two 
years  after,  without  manuring,  one-half  more  oat-corn 
and  straw  than  the  field  at  Mausegast,  and  in  the  fourth 
year  above  60  per  cent,  more  clover.  Now  some  of  the 
most  important  food  elements  of  corn  are  as  essential 
to  clover  as  to  the  cereals ;  and  the  food  elements  of 
oats  are  identical  with  those  of  rye. 


190 


THE   SYSTEM   OF  FAKM-YAKD   MANURING. 


A  larger  crop  of  any  of  the  cultivated  plants  given 
by  one  field  over  another  merely  indicates  that  the 
roots  in  the  one  field  in  their  way  downwards,  have 
found  and  absorbed  in  certain  portions  of  the  soil  more 
particles  of  the  whole  store  of  nutritive  substances  con- 
tained in  it  in  an  available  state  than  the  roots  in  the 
other  field ;  but  not  that  the  total  sum  was  greater  in 
the  one  than  in  the  other:  for  the  field  apparently 
poorer  might  in  reality  have  contained  a  much  larger 
total  amount  of  nutritive  substances  than  the  other, 
only  not  in  a  condition  available  to  the  roots. 

High  returns  are  a  sure  sign  that  the  nutritive  sub- 
stances of  the  soil  are  in  a  condition  available  to  the 
roots  ;  the  permanence  of  high  returns,  and  that  alone, 
affords  a  safe  criterion  of  the  total  store  or  quantity  of 
nutritive  substances  in  the  ground. 

The  high  returns  yielded  by  one  field  above  another 
result  from  this,  that  the  particles  of  the  mineral  con- 
stituents lie  nearer  together  in  the  one  field  than  in  the 
other  :  they  depend  upon  the  closeness  of  the  nutritive 
substances.  The  following  table  may  make  this  point 
clearer : — 


Cunnersdorf,  Mausegast,  Kotitz,  Oberbobritzsch,  Oberschona. 
Fig.  I.     1851.     WINTER- RYE. 


10  — -= 


ILLUSTKATION   OF  INCREASE   IN   CROPS.  191 

Fig.  II.     1852.    POTATOES. 


Fig.  III.     1853.     OATS. 


Fig.  IV.     1854.     CLOVER. 


In  Fig.  L,  the  perpendicular  lines  a  b  represent  the 
produce  of  grain,  a  c  that  of  straw ;  in  Fig.  II.,  the 
lines  d  e  the  produce  of  potatoes ;  in  Fig.  III.,  the  lines 


192  THE   SYSTEM   OF   FAKM-YARD   MANURING 

f  g  the  produce  of  oat-corn,  the  lines  f  h  that  of  oat- 
straw  ;  in  Fig.  IY.,  the  lines  i  ~k  the  produce  of  clover, 
on  the  unmanured  plots  of  ground  on  which  the  experi- 
ments were  made  in  Saxony. 

Now  if  we  assume  that  the  roots  of  the  rye  and  of 
the  other  plants,  on  the  several  fields,  were  of  the  same 
length  and  condition,  it  is  quite  certain  that  the  roots 
of  the  cereals  on  the  field  at  Mausegast  found,  in  their 
way  downwards,  much  more  nutriment  than  those  in 
the  Cunnersdorf  field :  the  corn  line  is  twice  as  high, 
and  the  straw-line  one-third  higher,  in  the  former  than 
in  the  latter. 

With  an  equal  number  of  plants,  and  an  equal 
length  of  root,  certain  nutritive  substances  required  by 
corn  were  twice  as  close  in  the  Mausegast  as  in  the 
Cunnersdorf  field.  The  line  in  Fig.  IV.  representing 
the  produce  of  clover  is  ten  times  as  high  for  Cunners- 
dorf as  for  Oberbobritzsch,  which  means  that  the  nutri- 
tive substances  required  by  clover  were  ten  times  as  far 
asunder  in  Oberbobritzsch  as  in  Cunnersdorf. 

In  comparing  the  produce  of  several  fields,  the  close- 
ness of  the  nutritive  substances  in  the  soil  is  in  inverse 
proportion  to  the  height  of  the  lines  in  the  table  indi- 
cating the  amount  of  produce. 

The  longer  the  lines,  the  closer  are  the  nutritive 
substances  in  the  various  soils ;  the  shorter  the  lines, 
the  more  widely  asunder  do  the  substances  lie. 

For  instance,  the  lines  indicating  the  produce  of 
potatoes  at  Kotitz  and  Oberbobritzsch  are  as  18  to  9  ; 
the  potato  crop  at  Kotitz  was  twice  as  high  as  that  at 
Oberbobritzsch.  Hence  it  follows  that  the  distance 
between  the  nutritive  substances  was  in  inverse  ratio, 
that  is,  as  9  to  18  ;  in  the  field  at  Kotitz  they  were 
twice  as  close  together  as  in  the  other. 

This  mode  of  viewing  the  matter  is  calculated  to 
lead,  in  many  cases,  to  more  definite  ideas  respecting 
the  cause  of  the  exhaustion  of  a  field. 

The  corn  and  potato  crops,  for  instance,  took  away 
phosphoric  acid  and  nitrogen  from  the  arable  surface 
soil  at  Mausegast,  and  the  barley  plant  next  in  rota- 


NEARNESS   OF   ELEMENTS   OF   FOOD   IN    SOILS.          193 

tion,  which  likewise  draws  its  nutriment  from  the  sur- 
face soil,  found  in  the  third  year  much  less  nutriment 
than  the  rye  plant  which  had  preceded  it. 

The  elevations  of  the  lines  a  b  (Fig.  I.)  andy  g  (Fig. 
III.),  taken  inversely,  show  how  much  relatively  greater 
has  become  the  distance  between  the  particles  of  the 
nutritive  substances  for  the  barley  plant.  The  barley- 
corn requires  for  its  formation  the  same  nutritive  sub- 
stances as  the  rye-corn.  Now,  as  the  produce  of  the 
rye-corn  was  to  that  of  the  barley-corn  in  the  proportion 
of  22  :  12,  this  means,  taken  inversely,  that  the  distance 
between  the  nutritive  substances  for  the  barley-corn  had 
increased  from  12  to  22. 

In  the  third  year,  the  roots  of  the  barley,  for  the 
same  length,  found  scarcely  half  as  much  nutriment  for 
grain  as  the  rye  had  found. 

This  exposition  is  not  intended  to  supply  a  standard 
for  measuring  the  distances  between  the  available  par- 
ticles of  nutritive  substances  in  the  ground,  but  merely 
to  define  more  accurately  what  is  meant  by  the  exhaus- 
tion of  land.  The  farmer  who  has  a  clear  view  of  the 
causes  upon  which  depends  the  reduction  of  crops  by 
continuous  cultivation,  will  thereby  the  more  easily  find 
out  and  apply  the  means  to  make  his  field  as  productive 
as  before,  and,  if  possible,  even  to  increase  its  fertility. 

Beside  the  general  differences  of  all  the  crops  in  the 
Saxon  experiments,  we  are  further  struck  with  the  in- 
equality in  the  proportion  of  corn  and  straw. 

To  10  parts  by  weight  of  corn,  the  yield  of  straw 
was  respectively — at  Cunnersdorf  25  parts  by  weight, 
at  Kotitz  23,  at  Oberschona  only  21,  and  at  Miiusegast 
only  20. 

A  more  careful  examination  of  the  table  shows  that 
the  difference  is  mainly  in  the  produce  of  corn. 

The  fields  at 

Cunnersdoi-f.  Kotitz.  Oberbobritzsch. 

Yielded  in  straw 2951  Ibs.  3013  Ibs.  3015  Ibs. 

that  is,  within  a  few  pounds,  the  same  quantity  of  straw, 
while  the  amount  of  corn  was  in 


194  THE    SYSTEM   OF    FARM-  YARD   MANURING. 

Cunnersdorf.  Kotitz.  Oberbobritzsch. 

11  :  12  :  14 

In  investigating  the  reasons  for  this  inequality  in  the 
produce  of  corn,  we  discover  at  the  same  time  the  causes 
of  the  difference  in  the  proportion  between  the  corn  and 
straw. 

It  is  necessary  to  remember  that  what  is  called  straw 
(i.  e.  the  leaves,  stalks,  and  roots)  is  formed  from  the  al- 
bumen of  the  cereal  seeds,  that  is,  from  the  constituent 
elements  of  the  seeds  ;  and,  further,  that  these  parts  of 
the  plant  are  the  organs  for  the  reproduction  of  these 
same  seed  constituents. 

The  production  of  the  straw  always  precedes  the 
formation  of  the  grain  ;  and  that  portion  of  the  seed 
elements  which  serves  to  form  the  organs  of  the  plant 
cannot  be  used  to  make  seed  :  or,  the  more  seed-con- 
stituents are  turned  into  straw-constituents  within  the 
appointed  time  of  growth,  the  fewer  will  remain  at  the 
close  of  that  period  for  the  formation  of  seed  (see  p.  63). 

Before  the  period  of  flowering,  all  the  seed-constitu- 
ents go  to  form  straw  ;  after  that  period,  a  division  takes 
place. 

Therefore,  if  all  other  conditions  of  soil  and  weather 
are  equally  favourable,  the  quantity  of  straw  will  de- 
pend upon  the  amount  of  seed-constituents  needed  for 
the  formation  of  straw. 

The  quantity  of  corn  depends  upon  the  residue  of 
seed-constituents  in  the  whole  plant,  which  are  no  longer 
required  for  the  multiplication  and  enlargement  of 
leaves,  stalks,  and  roots. 

Let  K  represent  that  portion  of  the  corn  constituents 
that  may  be  formed  into  seed  ;  dK  the  other  fraction  of 
the  same  substances,  wrhich  remain  as  constituents  in 
the  straw  ;  and  St  the  other  constituents  comprised  in 
the  straw  :  so  that 

K:=  (phosphoric  acid,  nitrogen,  potash,  lime,  magnesia,  iron), 
«K=a  fraction  of  K, 

acid,  potash,  lime,  magnesia,  iron); 


then  the  nutritive  substances  which  the  plant  has  ab- 
sorbed from  the  soil,  may  be  thus  expressed  :  — 


COKN   AND    STRAW    CONSTITUENTS    IN    SOILS.  195 

This  expression,  therefore,  means  that  the  roots  of 
the  cereal  plant  must  have  absorbed  from  the  earthy 
particles  in  contact  with  them  a  certain  proportion  of 
nutritive  substances  for  the  production  of  leaves,  roots, 
and  stalks,  and  after  this  an  additional  amount  of  sev- 
eral of  the  same  constituents  for  the  formation  of  grain. 
The  total  produce  is,  of  course,  dependent  upon  the  sum 
of  the  K  and  S£  constituents,  which  the  soil  is  able  to  sup- 
ply to  the  plants  during  the  natural  period  of  growth. 

The  ratio  between  corn  and  straw  results  from  a 
division  of  the  K  and  St  constituents  in  the  plant  itself, 
and  depends  upon  the  relative  proportion  of  the  K  and 
St  constituents  in  the  soil,  as  also  upon  the  action  of 
external  causes  favouring  the  production  of  corn  or 
straw. 

When  the  quantity  of  K  constituents  in  the  ground 
decreases,  less  grain  will  be  produced  ;  but  it  is  only  in 
certain  cases  that  this  will  exercise  any  influence  upon 
the  produce  of  straw. 

When  the  quantity  of  St  constituents  in  a  field  is 
increased,  the  enhanced  conditions  for  the  formation  of 
leaves,  stalks,  and  roots,  must  injure  the  crop  of  grain, 
if  the  amount  of  aK  required  for  the  additional  forma- 
tion of  straw  is  taken  from  the  store  of  K  contained  in 
the  soil. 

If  one  of  two  fields  is  poorer  in  K  but  richer  in  St 
constituents  than  the  other,  the  former  may  give  the 
same,  perhaps  even  a  larger,  amount  of  straw,  than  the 
latter,  but  its  produce  of  corn  will  necessarily  be  less. 

A  similar  increase  of  straw,  at  the  expense  of  grain, 
takes  place  when  the  state  of  the  weather  is  more  fa- 
vourable for  the  formation  of  leaves,  stalks,  and  roots, 
than  for  grain.  The  period  of  growth  is  thus  pro- 
longed, and  the  plant  then  takes  up  more  of  the  St  con- 
stituents, which  are  usually  in  excess  ;  for  the  assimila- 
tion of  these,  a  certain  additional  quantity  of  the  K 
constituents  is  consumed,  which  would  otherwise  have 
served  to  form  seed. 

Let  st  represent  the  additional  supply  of  St  constitu- 
ents afforded  by  the  soil  under  these  circumstances,  and 


196  THE   SYSTEM   OF   FARM- YARD   MANURING. 

ok  the  additional  portion  of  K  converted  into  straw- 
constituents  ;  then  the  alteration  in  the  produce  may 
be  expressed  as  follows  : — 

Corn.  Straw. 

(K  -  ak)  +  (oK  S*  +  ak  st) ; 

that  is,  the  produce  of  straw  increases,  while  that  of 
grain  diminishes.  It  is  also  evident,  that  where  the  St 
constituents  are  in  excess  and  the  amount  of  K  constitu- 
ents is  increased,  then  if  K  is  proportionately  deficient 
there  will  be  an  increase  in  the  produce  of  straw,  and  if 
K  is  proportionately  increased  there  will  be  a  larger 
produce  both  of  corn  and  straw. 

As  the  constituents  of  K,  with  the  exception  of  nitro- 
gen and  phosphoric  acid,  are  also  constituents  of  S£,  this 
accession  of  produce  in  the  field  under  consideration 
will  be  also  effected  either  by  a  supply  of  phosphoric 
acid,  or  of  nitrogen,  or  both  together. 

If  by  this  supply  the  closeness  of  the  K  particles  in 
the  ground,  or  of  the  phosphoric  acid  and  ammonia  par- 
ticles, is  doubled,  then  under  the  most  favourable  cir- 
cumstances the  harvest  may  be  doubled  by  the  supply 
ofK. 

If,  on  the  other  hand,  the  soil  is  deficient  in  St  con- 
stituents, any  increase  of  nitrogen  or  phosphoric  acid  in 
the  ground  will  fail  to  exercise  the  slightest  influence 
upon  the  crop. 

It  results  from  this,  as  a  matter  of  course,  that  the 
absolute  or  relative  amount  of  straw,  given  by  a  field  in 
a  crop  of  corn,  will  furnish  no  proof  of  the  St  constituents 
in  the  soil :  since,  though  two  fields  may  be  equally  rich 
in  these  constituents,  the  produce  of  straw  depends  upon 
the  quantity  of  K  constituents  in  the  ground :  hence 
the  field  which  is  richer  in  K,  will,  under  like  circum- 
stances, give  a  larger  crop  of  straw. 

The  fact,  therefore,  that  the  fields  at  Cunnersdorf 
and  Oberbobritzsch  yielded  a  like  amount  of  straw, 
cannot  lead  to  the  inference  that  these  fields  contained 
an  equal  quantity  of  St  constituents,  since  the  corn 
crops  show  that  the  quantities  of  K  were  unequal.  The 
harvests  exhibited  the  following  proportions  : — 


RELATIVE    PROPORTION    OF    CORN   AND    STRAW.        197 

In  Cunnersdorf  as (11)  K  :  (29)  aK  St. 

"  Kotitz  as (12)  K  :  (30)  aK  St. 

"  Oberbobritzsch  as (14)  K  :  (30)  aK  St. 

As  before  remarked,  the  constituents  represented  by 
the  symbols  K  and  S£  differ  merely  in  this,  that  K  com- 
prises nitrogen  and  phosphoric  acid,  while  the  other 
constituents  of  K  are  common  to  both ;  hence  the  dif- 
ference in  the  corn  crops  of  these  three  fields  results 
mainly  from  the  fact,  that  the  roots  of  the  corn  found 
in  the  soil  at  Kotitz  -f\  and  at  Oberbobritzsch  T3r  more 
phosphoric  acid  and  nitrogen  in  an  available  condition 
than  at  Cunnersdorf. 

If  the  question  is  asked,  how  much  phosphoric  acid 
and  nitrogen  must  be  added  to  the  field  at  Cunnersdorf 
in  order  to  make  the  crop  of  corn  equal  to  that  of  Ober- 
bobritzsch, it  would  be  a  mistake  to  suppose  that  an 
increase  of  T3T  would  be  sufficient ;  for  the  augmenta- 
tion of  the  produce  of  corn  is  materially  influenced  by 
the  S£  constituents,  the  quantity  of  which  varies  greatly 
in  different  soils  and  has  not  been  ascertained. 

By  the  addition  of  nitrogen  and  phosphoric  acid,  a 
certain  quantity  of  the  accumulated  S£  constituents  are 
rendered  effective  or  available,  which  before  were  not 
so  ;  but  while  the  produce  of  straw  increases,  not  T3T, 
but  less  of  nitrogen  and  phosphoric  acid  remain  over  for 
the  formation  of  seed  ;  the  exact  quantity  is  limited  by 
the  total  amount  of  transformed  St  constituents. 

The  closeness  of  the  Stf  constituents  in  different  soils 
may,  however,  be  approximately  ascertained  from  the 
relative  proportion  of  corn  and  straw  obtained  from  a 
plot  manured  with  phosphoric  acid  and  nitrogen,  and 
from  an  unmanured  plot  respectively. 

If  the  unmanured  plot  yields  corn  and  straw  in  the 
proportion  of  1  :  2*5,  and  the  manured  plot  gives  a 
larger  crop  in  which  the  corn  is  to  the  straw  as  1  :  4 
(straw  being  in  greater  proportion),  it  is  evident  that 
the  St  constituents  preponderate  in  the  latter  field  ;  and 
a  much  larger  quantity  of  phosphoric  acid  and  nitrogen 
would  have  to  be  supplied  in  order  that  the  field,  cor- 
respondently  with  its  amount  of  Srf  constituents,  might 


198 


THE   SYSTEM   OF  FARM- YARD   MANURING. 


produce  the  same  relative  proportion  of  corn  and  straw 
as,  for  example,  the  land  at  Oberbobritzsch. 

It  is  a  very  essential  part  of  the  farmer's  business  to 
study  the  nature  of  his  field,  and  to  discover  which  of 
the  nutritive  substances,  useful  to  plants,  his  land  con- 
tains in  preponderating  quantity :  for  thus  he  will  know 
how  to  make  a  right  selection  of  such  plants  as  require 
for  their  developement  a  superabundance  of  these  con- 
stituents ;  and  he  will  obtain  the  greatest  profit  from  his 
field,  when  he  knows  what  nutritive  substances  he 
must  supply  in  due  proportion  to  those  which  are 
already  in  abundance. 

Two  fields,  in  which  the  total  amount  of  nutriment 
is  unequal,  but  the  relative  distribution  of  the  sub- 
stances is  the  same,  will  produce  crops  differing  in 
quantity,  but  agreeing  in  the  relative  proportion  be- 
tween corn  and  straw. 

Such  a  relation,  for  example,  exists  between  the 
field  at  Oberbobritzsch  and  the  field  at  Mausegast.  If 
the  crop  of  corn  and  straw  in  the  former  is  expressed  by 
~K.  +  aK  St,  the  crop  in  the  latter  =  l^K  +  l^K  St. 

The  fields  are  evidently  cultivated  in  both  places 
with  great  care  and  skill,  and  the  soil  is  so  uniformly 
mixed,  that  when  we  know  the  corn  and  straw  crop  of 
the  one,  and  the  straw  crop  of  the  other,  we  can  calcu- 
late the  corn  crop  of  the  latter  from  the  above  formula. 

Potatoes,  1852. — In  the  subjoined  table,  the  vertical 
lines  show  the  potato  crops  from  five  different  fields  in 
the  year  1852. 

1852.    POTATOES. 
Cunnersdorf,  Mausegast,  Kotitz,  Oberbobritzsch,  Oberschona. 


A   POTATO-CROP   AND   THE   MINERALS   IN   THE   SOIL.       199 

The  potato  plant  draws  its  principal  constituents 
from  the  arable  surface  soil,  and  from  a  somewhat 
deeper  layer  than  the  rye  plant ;  and  the  crops  reaped 
show  the  condition  of  the  layers  more  accurately  than 
could  be  ascertained  by  chemical  analysis. 

In  the  fields  at  Mausegast  and  Cunnersdorf  the  nu- 
tritive substances  available  for  the  potato  plant  were 
about  equally  close ;  in  Kotitz  they  were  one-ninth 
closer  to  each  other  ;  at  Oberbobritzseh  they  were  twice 
as  far  asunder ;  while  at  Oberschona  they  were  one-fifth 
closer  than  in  Oberbobritzsch. 

The  largest  potato  crop  was  obtained  from  the  field  at 
Kotitz.  Potash  (for  the  tubers)  and  lime  (for  the  herb- 
aceous parts)  are  the  predominant  constituents  of  the 
potato  plant :  but  a  certain  amount  of  nitrogen  and 
phosphoric  acid  is  as  necessary  for  the  development  of 
the  potato  as  it  is  for  cereals  ;  and  the  effective  quan- 
tity of  the  transmuted  potash  and  lime  is  essentially 
determined  by  the  phosphoric  acid  and  nitrogen  ab- 
sorbed at  the  same  time.  Where  one  of  the  two  latter 
elements  which,  as  we  have  remarked,  are  equally  con- 
stituents of  cereals,  is  deficient  in  the  soil,  the  potato 
crop  will  be  proportionate  to  the  available  quantity  of 
these  two  substances,  and  the  greatest  excess  of  potash 
or  lime  in  the  soil  will  have  no  influence  whatever  upon 
the  amount  of  the  produce. 

The  arable  surface  soil  of  the  field  at  Oberbobritzsch 
is  much  richer  in  phosphoric  acid  and  nitrogen  than 
that  of  the  Kotitz  field  ;  yet  the  potato  crop  yielded  by 
the  former  was  only  half  that  given  by  the  latter. 

Accordingly,  nothing  can  be  more  certain  than  that 
the  field  at  Oberbobritzsch  contained  much  less  potash 
or  lime  in  an  available  state,  than  the  Kotitz  field ;  and 
by  manuring  with  lime  alone,  or  with  wood-ashes  (pot- 
ash and  lime),  it  might  readily  be  ascertained  in  which 
of  the  two  substances  the  ground  was  deficient. 

But  from  the  inferior  potato  crop  given  by  the  field 
at  Cunnersdorf,  we  cannot  infer  that  it  was  poorer  in 
potash  or  lime  than  the  field  at  Kotitz  ;  the  latter  de- 
cidedly contained,  as  the  preceding  corn  crop  shows, 


200 


THE    SYSTEM   OF   FARM-YAKD   MANURING. 


somewhat  more  phosphoric  acid  and  nitrogen  than  the 
field  at  Cunnersdorf :  consequently,  the  larger  potato 
crop  at  Kotitz  may  have  been  mainly  owing  to  the 
greater  quantity  of  these  two  elements  contained  in  it. 
Even  if  the  field  at  Cunnersdorf  had  been  still  richer  in 
potash  and  lime  than  the  Kotitz  field,  yet  after  all, 
under  the  given  conditions,  it  would  have  produced  a 
smaller  crop  of  potatoes. 

Oats,  1853. — The  oat  plant  derives  part  of  its  nutri- 
ment from  the  arable  surface  soil,  but  sends  its  roots, 
when  the  soil  permits,  much  deeper  than  the  potato  ;  it 
possesses,  so  to  speak,  a  higher  power  of  vegetation  than 
the  rye  plant,  and  in  the  faculty  of  appropriating  nutri- 
ment resembles  weeds. 

1853.     OATS. 
Cunnersdorf,  Miiusegast,  Kotitz,  Oberbobritzsch,  Oberschona. 


The  point  which  most  strikes  us  in  this  table  is  the 
great  inequality  in  the  produce  of  two  cereal  plants 
grown  successively  on  the  same  unmanured  soil. 

The  field  at  Cunnersdorf,  which  next  to  that  at  Ober- 
schona had  given  the  lowest  crop  of  rye-corn  and  straw, 
yielded  in  the  third  year  the  largest  produce  of  oat-corn 
and  straw. 

The  difference  in  the  condition  and  closeness  of  the 
nutritive  substances  in  the  lower  layers  of  these  fields  is 
undeniable.  The  field  at  Cunnersdorf  was  poorer  in 
the  upper  layers,  but  went  on  increasing  downwards 
in  the  amount  of  substances  nutritive  to  the  corn  plant ; 
the  other  fields  decreased  downwards. 

The  returns  of  the  field  at  Mausegast  for  the  year 
1853  refer  to  barley  and  not  to  oats :  hence  they  afford  no 
conclusion  as  to  the  condition  of  the  deeper  layers,  from 


CLOVER  CHOPS  AND  THE  MINERALS   IN  THE   SOIL.      201 


which  the  oat  plant  derives  its  food  :  but  they  show  the 
state  into  which  the  arable  surface  soil  had  been  brought 
by  the  preceding  corn  crop.  Owing  to  the  abstraction 
of  phosphoric  acid,  and  perhaps  of  nitrogen,  the  yield 
of  barley-corn  was  much  less  than  might  have  been  ex- 
pected from  the  soil,  judging  by  the  preceding  rye  crop ; 
and  a  small  supply  of  superphosphate  or  guano  would 
have  greatly  increased  the  produce  of  barley  on  this 
field. 

Clover,  1854. — The  clover  crops  in  the  fourth  year 
afford  an  insight  into  the  condition  of  the  deepest  layers 
from  which  plants  draw  their  food. 

1854.     CLOVER. 
Cunnersdorf,  Mausegast,  Kotitz,  Oberbobritzsch,  Oberschona. 


The  produce  of  clover  at  Cunnersdorf  was  nearly 
twice  as  large  as  at  Mausegast,  and  ten  times  greater 
than  at  Oberbobritzsch ;  and  it  is  beyond  doubt,  that 
these  unequal  crops  must  have  corresponded  to  unequal 
amounts  in  the  soil  of  substances  nutritive  to  the  clover 
plant. 

The  substances  required  by  the  clover  plant,  in  re- 
spect of  quantity  and  relative  proportion,  are  very 
nearly  the  same  as  for  the  potato  plant  (leaves,  stalks, 

9* 


202  THE   SYSTEM   OF   FARM-YARD   MANURING. 

and  tubers  included) :  and  if  clover  still  yields  good 
crops  upon  a  soil  wherein  potatoes  thrive  but  imper- 
fectly, this  is  chiefly  owing  to  the  wider  root-ramifica- 
tion of  the  clover  plant.  There  are  scarcely  any  two 
other  plants  which  so  clearly  indicate  the  layers  of  the 
soil  assigned  to  them  by  nature,  for  the  absorption  of 
their  nutriment. 

If  potatoes  are  planted  in  trenches  two  feet  deep, 
and  if  these  are  filled  up  in  proportion  as  the  plant 
grows,  so  that  at  last  the  earth  in  the  trench  is  on  the 
same  level  with  the  arable  surface,  it  is  always  found 
that  the  tubers  are  formed  only  in  the  topmost  layer, 
none  at  a  greater  depth,  and  not  more  in  number  than 
if  the  seed-potatoes  had  been  planted  only  1-J-  or  2 
inches  deep  in  the  arable  surface  soil :  and  on  gathering 
the  crop  it  is  observed  that  the  roots  below  the  arable 
surface  have  died  away. 

"With  clover,  the  case  is  reversed  ;  and  although  the 
arable  surface  soil  at  Kotitz,  for  example,  is  decidedly 
richer  in  substances  nutritive  for  clover  than  that  in 
Cunnersdorf  (yielding  a  potato  crop  higher  by  one- 
eighth),  this  had  no  effect  upon  the  clover,  which 
receives  its  principal  nutriment  from  the  deepest  layers 
of  the  soil. 

We  now  proceed  to  an  analysis  of  the  returns  which 
were  obtained,  in  the  Saxon  experiments,  by  employing 
farm-yard  manure  upon  the  plots  of  the  same  fields, 
the  crops  of  which  in  their  unmanured  state  we  have 
just  been  considering. 


THE  PRODUCE  NOT  IN  PROPORTION  TO  THE  MANURE.  203 


Produce,  per  Saxon  acre,  of  the  fields  dressed  with  farm-yard 
manure. 


Cunnersdorf. 

Mausegast. 

Kotitz. 

Oberbobritzsch 

Oberschona. 

Farm-yard        ) 
manure.  .  .  j" 

cwt. 
180 

cwt. 
194 

cwt. 

229 

cwt. 
314 

cwt. 

897 

1851. 
Rye  corn  .... 
"    straw  .... 

Ibs. 
1513 
4696 

Ibs. 
2583 
5318 

Ibs. 
1616 
4019 

Ibs. 
1905 
3928 

Ibs. 
1875 
3818 

1852. 
Potatoes  

17946 

20258 

20678 

11936 

16727 

1853. 
Oat  corn  
"    straw  

2278 
2992 

1649 
2475 

1880 
1742 

1685 
1909 

1253 
2576 

1854. 
Clover-hay.  .  .  . 

9509 

7198 

1232 

2735 

0* 

Increase  fiy  farm-yard  manure  over  unmanured  plots.  (See  p.  186.) 


Cunnersdorf. 

Mausegast. 

Kotitz. 

Oberbobiitzsch. 

Oberschona. 

1851. 
Rye  corn  .... 

"    straw.  .  .  . 

Ibs. 

337 
1745 

Ibs. 

345 

736 

Ibs. 

352 
1006 

Ibs. 

452 
915 

Ibs. 

1167 

229 

1852. 
Potatoes  

1279 

3362 

2101 

2185 

5632 

1853. 
Oat  corn  
"    straw  .... 

369 
429 

360 
635 

541 

385 

157 
97 

171 

862 

1854. 
Clover-hay  .  .  . 

365 

1615 

137 

1824 

* 

Here,  again,  what  strikes  us  first  is  that  the  returns 
from  all  the  fields  were  different  from  one  another,  and 
that  apparently  they  did  not  bear  the  most  remote  rela- 
tion to  the  quantity  of  manure  applied. 

Nothing  can  be  more  certain  than  the  fact  that  a 
field,  exhausted  by  cultivation,  will  yield  larger  returns 
if  dressed  with  farm-yard  manure  than  if  unmanured  : 

*  The  clover  crop  failed  from  excessive  wet. 


204 


THE   SYSTEM   OF  FAEM-YAKD   MANURING. 


now,  taking  the  increase  to  be  caused  by  manure,  it  is 
natural  to  suppose  that  the  same  quantity  of  manure 
would  produce  the  same  increase  upon  different  fields. 
The  following  table,  however,  shows  that  the  same 
quantity  of  manure,  upon  the  Saxon  fields,  produced 
results  which  differed  very  considerably. 

One  hundred  cwt.  of  farm-yard  manure  gave  increased  produce. 


Cunnersdorf. 

Mausegast. 

Kotitz. 

Oberbobritzsch. 

Oberschbna. 

Ibs. 

Ibs. 

Ibs. 

Ibs. 

Ibs. 

1851-53. 

Winter  rye  &  ) 
oats  f 

1539 

1070 

988 

515 

501 

1852. 

Potatoes 

720 

1723 

917 

696 

628 

1854. 

Clover       .     .  . 

203 

832 

60 

628 

No  one  looking  at  these  numbers  could  divine  that 
they  were  intended  to  represent  the  effects  produced 
upon  five  different  fields  by  an  equal  quantity  of  the 
same  manure,  and  that  too  the  universal  manuring 
agent. 

Neither  in  the  crop  of  rye-corn  and  straw,  nor  in 
that  of  potatoes,  oats,  and  clover,  is  there  the  slightest 
resemblance  or  correspondence ;  still  less  is  it  possible 
to  discover  what  amount  of  manure  has  been  instru- 
mental in  producing  the  increased  crops. 

The  same  quantity  of  farm-yard  manure  gave,  in  the 
years  1851  and  1853J  at  Mausegast  double,  at  Cunners- 
dorf three  times,  the  increase  of  cereal  crops,  corn  and 
straw  together,  that  was  obtained  at  Oberbobritzsch : 
the  increase  of  the  potato  crop  at  Mausegast  was  twice 
as  large  as  in  Kotitz ;  of  clover,  four  times  more  in 
Mausegast  than  in  Cunnersdorf;  and  in  Oberbobritzsch, 
ten  times  as  much  as  in  Kotitz. 

The  enormous  quantity  of  farm-yard  manure  put 
upon  the  field  at  Oberschona  failed  to  produce  anything 
like  the  crop  obtained  from  the  unmanured  field  at 
Mausegast. 


,  CEOPS   FEOM  FAEM-YAED   MANURE  VARY. 


205 


The  composition  of  farm-yard  manure,  as  we  know 
from  numerous  analyses,  is  on  the  whole  so  much  alike 
in  all  places,  that  we  may  suppose  without  great  risk  of 
error  that  in  100  cwt.  of  farm-yard  manure  every  iield 
receives  the  same  nutritive  substances  and  in  the  same 
quantities. 

The  constituents  of  farm-yard  manure  act  every- 
where in  the  same  way  upon  the  soil  or  the  earthy  par- 
ticles. Now  this  apparently  involves  an  irreconcilable 
contradiction  with  the  fact  that  the  increase  obtained  by 
it  is  nevertheless  everywhere  different,  and  that  the 
dung-constituents  supplied  will,  on  one  field,  set  in 
motion  and  render  available  to  the  cereal  or  potato 
plants  growing  on  it,  twice  or  three  times  as  many  ele- 
ments of  food  as  on  another  field. 

This  fact  does  not  refer  to  the  Saxon  fields  alone, 
but  applies  generally.  Nowhere,  in  no  country,  do  the 
crops  obtained  by  farm-yard  manuring  on  different 
fields  ever  correspond,  as  the  following  table  of  the 
average  produce  of  divers  crops  in  different  provinces 
of  the  kingdom  of  Bavaria  will  show. 

AVERAGE  CROPS  IN  BAYARIA. 

(Seu/erfs  Statistics.) 
One  day's  work  yields  average  produce  in  bushels.* 


Wheat. 

Eye. 

Spelt. 

Barley. 

Oats. 

Upper  Bavaria  

1-70 

1-80 

3-40 

1-90 

2'31 

Lower  Bavaria. 

2*50 

1-80 

3'40 

1*90 

2*31 

Upper  Palatinate  and  Ratisbon  .  . 

1-45 
T20 

1-40 
1-30 

2-70 
2'20 

1-75 
1-50 

1-85 
1-75 

Middle  Franconia  

1-65 

1-40 

3'50 

1'65 

2-25 

Lower  Franconia  and  Ashaffenburg 
Suabia  and  Neuburg  

1-70 

1-80 

1-75 

2  -00 

2'50 
5'0 

2-00 
2*30 

2-75 
3'50 

Palatinate  

2-70 

2-60 

4-80 

3'75 

3-90 

*  1  Hectolitre 


Wheat 146  Ibs. 

Barley 128    " 

Rye 140  " 

Oats 88    " 

Spelt  (in  the  husk) 79   " 


s  on  an  average     1  Bavarian  bushel. 

Zollverein  weight.     Zollverein  weight. 
330—345  Ibs. 
290—300    " 
318—325    " 
200—300    " 


174—220 


According  to  this  scale,  the  weight  of  a  Prussian  bushel  of  wheat  is 


206  THE    SYSTEM    OF   FARM-YARD   MANURING. 

The  crops  produced  by  farm-yard  manuring  differ 
not  only  in  every  country,  but  even  in  every  locality ; 
and,  strictly  speaking,  every  field  dressed  with  farm- 
yard manure  yields  an  average  produce  of  its  own. 

The  action  of  farm-yard  manure  upon  the  increase 
of  produce  is  intimately  connected  with  the  condition 
and  composition  of  the  soil ;  it  varies,  therefore,  in  dif- 
ferent fields,  simply  because  the  composition  of  the  soil 
varies. 

To  understand  the  action  of  farm-yard  manure,  it  is 
necessary  to  remember  that  the  exhaustion  of  a  field 
arises  from  the  loss  of  a  certain  amount  of  nutritive  con- 
stituents, at  the  end  of  a  rotation,  inflicted  upon  the 
soil  by  preceding  crops,  which  of  course  leave  less  avail- 
able food  in  the  soil  for  the  following  crops. 

However,  the  loss  of  each  individual  constituent  has 
not  the  same  effect  upon  the  exhaustion  of  the  soil. 

The  loss  of  lime  which  a  calcareous  soil  suffers  by  a 
cereal  or  by  clover,  matters  little  to  the  growth  of  a 
succeeding  plant  that  requires  large  quantities  of  lime 
to  thrive  well.  The  same  applies  equally  to  the  loss  of 

Eotash,  magnesia,  iron,  phosphoric  acid,  nitrogen,  on 
elds  severally  abounding  in  potash,  magnesia,  iron, 
phosphoric  acid,  or  ammonia.  Where  a  soil  is  abun- 
dantly provided  with  one  of  the  mineral  constituents,  the 
amount  of  that  constituent  removed  by  the  crops  is  so 
small  a  fraction  of  the  whole  mass,  that  the  effect  of  the 
diminished  store  is  not  appreciable  from  one  rotation  to 
another. 

But  practical  experience  shows  that  the  crops  do  de- 
crease from  one  rotation  to  another,  and  that  the  land 
requires  a  fresh  supply  of  certain  ingredients  by  manur- 
ing, if  it  is  again  to  produce  as  large  harvests  as  before. 
JSTow,  as  a  supply  of  lime  cannot  be  expected  to  re- 
store the  fertility  of  an  exhausted  field  where  lime  con- 
stitutes the  principal  bulk  of  the  soil,  just  as  little  as  a 
supply  of  potash  or  phosphoric  acid  to  a  field  abounding 
in  potash  or  phosphoric  acid,  it  is  easy  to  understand 

83  Ibs.,  and  that  of  the  English  quarter  425  Ibs.,  100  Ibs.  (Zollv.  weight 
=  110-2  Ibs.  avoir.). 


CROPS,    HOW   GOVEKNED.  207 

that  where  the  productive  power  of  an  exhausted  field 
is  restored,  the  fertilising  effect  is  to  be  attributed  sim- 
ply to  the  manure  returning  to  the  field  those  elements 
of  food  which  the  soil  originally  contained  in  the  least 
proportion,  and  of  which  it  has  accordingly  lost,  by  the 
preceding  crops,  comparatively  the  largest  fraction. 

Every  field  contains  a  maximum  of  one  or  several, 
and  a  minimum  of  one  or  several,  other  nutritive  sub- 
stances. It  is  by  the  minimum  that  the  crops  are  gov- 
erned, be  it  lime,  potash,  nitrogen,  phosphoric  acid, 
magnesia,  or  any  other  mineral  constituent ;  it  regu- 
lates and  determines  the  amount  or  continuance  of  the 
crops. 

Where  lime  or  magnesia,  for  instance,  is  the  mini- 
mum constituent,  the  produce  of  corn  and  straw,  tur- 
nips, potatoes,  or  clover,  will  not  be  increased  by  a  sup- 
ply of  even  a  hundred  times  the  actual  store  of  potash, 
phosphoric  acid,  silicic  acid,  &c.,  in  the  ground.  But 
a  simple  dressing  with  lime  will  increase  the  crops  on 
a  field  of  the  kind,  and  a  much  larger  produce  of  cere- 
als, turnips,  and  clover  will  be  obtained  by  the  use  of 
this  agent  (just  as  is  the  case  by  the  application  of 
wood-ashes  on  a  field  deficient  in  potash)  than  by  the 
most  liberal  use  of  farm-yard  manure. 

This  sufficiently  explains  the  dissimilar  action  upon 
different  fields  of  so  composite  a  manure  as  farm-yard 
dung. 

Only  those  ingredients  of  farm-yard  manure  which 
serve  to  supply  an  existing  deficiency  of  one  or  two  of 
the  mineral  constituents  in  the  soil  act  favourably  in 
restoring  the  original  fertility  to  a  field  exhausted  by 
cultivation ;  all  the  other  ingredients  of  the  manure, 
which  the  field  contains  in  abundance,  are  completely 
without  effect.. 

A  field  rich  in  straw-constituents  cannot  be  made 
more  productive  by  manuring  with  straw-constituents 
in  the  dung,  whereas  these  constituents  will  prove  most 
efficacious  on  fields  deficient  in  them. 

If  two  fields  have  the  same  abundance  of  straw-con- 
stituents, but  are  not  equally  rich  in  corn  constituents, 


208  THE   SYSTEM   OF   FAKM-YAKD   MANUEING. 

the  same  supply  of  farm-yard  manure  will  not  produce, 
by  any  means,  equal  crops  of  corn,  because  these  must 
bear  a  relation  to  the  corn -constituents  supplied  in  the 
manure.  Of  these,  both  fields  received  the  same 
amount  in  the  same  quantity  of  manure ;  but  as  the 
one  field,  of  itself,  was  richer  in  corn-constituents  than 
the  other,  the  poorer  of  the  two  must  receive  much 
more  manure  to  make  it  produce  as  large  crops  as  the 
other. 

A  comparatively  small  quantity  of  superphosphate 
will,  on  a  field  of  the  kind,  serve  to  increase  the  produce 
to  a  much  greater  extent,  than  the  most  liberal  use  of 
farm-yard  manure. 

Upon  a  field  deficient  in  potash  farm-yard  manure 
acts  by  the  potash  contained  in  it ;  upon  a  soil  poor  in 
magnesia  or  lime,  by  its  magnesia  or  lime ;  upon  one 
poor  in  silicic  acid,  by  the  straw  in  it ;  upon  land  poor 
in  chloride  or  iron,  by  the  chloride  of  sodium,  chloride 
of  potassium,  or  iron  contained  therein. 

This  fact  accounts  for  the  high  favour  in  which 
farm-yard  manure  is  held  by  practical  farmers.  As  the 
dung  of  the  farm-yard  contains,  under  all  circumstances, 
a  certain  quantity  of  each  of  the  mineral  constituents 
withdrawn  from  the  soil  by  the  crops  grown  on  it,  its 
action  is  universally  beneficial.  It  never  fails  to  pro- 
duce the  desired  effect,  and  thus  spares  the  practical 
man  the  trouble  of  devising  more  suitable  and  equally 
efficacious  means  for  keeping  up  the  fertility  of  his 
fields,  with  a  less  profuse  expenditure  of  money  and 
labour,  or  of  raising  his  land,  without  additional  outlay, 
to  the  highest  attainable  degree  of  fertility  compatible 
with  its  composition. 

It  is  well-known  in  practice,  that  the  produce  of 
many  fields  may  be  increased  by  manuring  with  guano, 
bone-dust,  rage-cake,  and  other  substances  containing 
only  certain  constituents  of  farm-yard  manure ;.  and 
their  operation  is  explained,  in  effect,  by  the  doctrine 
of  mimmum,  which  I  have  just  laid  down. 

But  as  the  practical  farmer  is  not  acquainted  with 
the  law  which  regulates  the  operation  of  these  manur- 


ERROR   IN"   USING   TOO   MUCH   MANURE.  209 

ing  agents  as  affecting  the  increase  of  produce,  he  can, 
of  course,  have  no  correct  notion  of  their  rational,  which 
means  their  truly  economical,  use  ;  he  puts  on  his  land 
too  much,  or  too  little,  or  chooses  the  wrong  agent. 
The  error  of  employing  too  little  manure  needs  no  ex- 
planation ;  for  every  one  knows  that  the  right  propor- 
tion of  manure  will,  with  exactly  the  same  labour  and 
at  a  trifling  additional  outlay,  ensure  the  maximum 
produce  of  which  the  land  is  capable. 

The  error  of  using  too  much  manure  arises  from  the 
mistaken  notion  that  the  action  of  manures  is  propor- 
tionate to  the  quantities  in  which  they  are  applied ; 
this  is  true  up  to  a  certain  limit,  but  beyond  this  all  the 
manure  applied  is  simply  thrown  away,  as  far  as  any 
fertilising  action  is  concerned. 

A  manuring  experiment  made  by  Mr.  J.  RUSSELL, 
of  Craigie  House  ('  Journal  of  the  Royal  Agr.  Soc.  of 
England,'  vol.  xxii.  p.  86),  may,  perhaps,  serve  to  illus- 
trate our  meaning.  In  this  experiment  a  field  was 
divided  into  a  number  of  plots  of  three  rows  each,  all 
planted  with  turnips,  some  of  the  plots  being  left  un- 
manured,  the  remainder  dressed  severally  with  different 
manuring  agents,  among  others  with  superphosphate 
(bone-ash  dissolved  in  sulphuric  acid).  The  produce, 
calculated  per  acre,  was  as  follows  : — 

Produce  per  acre. 

"No.  of  plots.  Cwt. 

I.  Unmanned 340  turnips  (Swedes). 

II.  "          320 

V.  Manured  with  5  cwt.  of  superphosphate  535 


VI.  "  5 

VII.  "  3 

VIII.  "  7 

IX.  "  10 


497 
480 
499 
490 


As  shown  by^he  difference  of  20  cwt.  in  the  produce 
of  the  unmanured  plots,  the  condition  of  the  soil  and 
the  store  of  mineral  constituents  differed,  to  some  ex- 
tent, in  different  parts  of  the  field.  Other  experiments, 
which  we  cannot  describe  more  particularly,  showed 
that  the  soil  was-  poorer  in  the  centre  of  the  field  than 
on  the  sides. 


210  THE   SYSTEM   OF   FARM-YAKD   MANURING. 

The  one  great  fact  most  clearly  proved  by  the  above 
table  of  produce  is,  that  3  cwt.  of  superphosphate  gave 
nearly  the  same  crop  of  turnips  as  5  cwt. ;  and  that  a 
further  increase  of  the  manure  to  10  cwt.  produced  no 
additional  increase  of  the  crop. 

No  steps  were  taken,  in  these  experiments,  to  ascer- 
tain which  of  the  constituents  of  superphosphate  of  lime 
had  the  principal  share  in  increasing  the  produce  of  the 
field.  Magnesia  and  lime,  as  well  as  sulphuric  and 
phosphoric  acid,  are  equally  indispensable  elements  of 
food  for  the  turnip  plant ;  and  I  have  observed  that  by 
manuring  with  gypsum  and  a  little  common  salt  or  with 
phosphate  of  magnesia,  a  field  will  be  made  to  give 
more  abundant  crops  than  by  employing  superphos- 
phate of  lime,  although  the  latter  unquestionably  proves 
the  most  effective  manure  for  most  fields. 

To  apprehend  these  facts  correctly,  we  must  remem- 
ber that  the  law  of  the  minimum  does  not  apply  to  one 
constituent  alone,  but  to  all.  Where,  in  any  given  case, 
the  crops  of  any  plant  are  limited  by  a  minimum  of 
phosphoric  acid  in  the  field,  these  crops  will  increase 
by  augmenting  the  quantity  of  phosphoric  acid  up  to 
the  point  at  which  the  additional  phosphoric  acid  bears 
a  proper  proportion  to  the  next  minimum  constituent 
in  the  soil. 

If  the  additional  phosphoric  acid  exceeds  the  corre- 
sponding quantity,  for  instance,  of  potash  or  ammonia 
in  the  soil,  the  excess  will  prove  of  no  effect.  Before 
the  supply  of  phosphoric  acid  the  available  quantity  of 
potash  or  ammonia  was  a  little  larger  than  the  amount 
of  phosphoric  acid  in  the  soil,  and  the  excess  of  the 
alkalies  was  ineffective  until  the  phosphoric  acid  was 
supplied  ;  similarly  the  excess  of  phosphoric  acid  must 
remain  just  as  inoperative,  as  previously  the  excess  of 
potash. 

"Whilst  the  produce  before  was  proportionate  to  the 
minimum  of  phosphoric  acid,  it  is  now  in  proportion  to 
the  minimum  of  potash  or  ammonia,  or  both  alkalies. 
A  few  experiments  made  on  Mr.  Russell's  field  might 
have  settled  the  question.  Had  potash  or  ammonia 


THE   LAW   OF   MINIMUM.  211 

been  the  minimum,  after  manuring  with  superphos- 
phate, a  suitable  supply  of  potash  or  ammonia,  or  both, 
would  have  increased  the  produce.  In  this  same  series 
of  experiments,  6  cwt.  of  guano,  corresponding  to  2  cwt. 
of  superphosphate,  gave  a  crop  of  630  cwt.  of  turnips, 
or  130  cwt.  more  than  the  superphosphate ;  but  it  is 
left  in  doubt  whether  this  increase  was  attributable  to 
the  potash  or  the  ammonia  in  the  guano. 

To  return  to  our  Saxon  experiments.  If  we  look  at 
the  different  quantities  of  dung  applied  severally  on 
the  five  fields,  we  are  naturally  led  to  inquire  the 
reason  of  this  diversity. 

The  most  feasible  answer,  perhaps,  is,  that  the  far- 
mer gives  as  much  manure  as  he  has  at  his  disposal,  or 
that  he  regulates  the  quantity  according  to  certain 
facts.  If  he  has  found  by  experience  that  a  certain 
quantity  of  farm-yard  manure  will  restore  his  land  to 
its  original  fertility,  and  that  more  copious  manuring 
will  fail  to  give  larger  crops,  in  proportion  to  the  addi- 
tional supply,  or  to  the  cost  incurred  in  collecting  the 
manure,  he  will  stop  at  the  smaller  quantity. 

Hence  it  cannot  be  regarded  as  a  mere  accident  that 
the  farmer  at  Cunnersdorf  contented  himself  with  180 
cwt.  of  farm-yard  manure,  while  the  farmer  at  Ober- 
bobritzsch  laid  314  cwt.  upon  his  field. 

But  if  the  quantity  of  manure  to  be  applied  is  not 
dependent  upon  chance  or  caprice,  but  is  regulated  by 
the  object  in  view,  it  is  manifest  that  the  proceedings 
of  the  farmer  are  governed  by  a  law  of  nature  unknown 
to  him,  except  by  its  effects. 

It  is  in  the  composition  and  condition  of  the  soil 
that  we  must  seek  the  law  which  regulates  the  quantity 
of  farm-yard  manure  required,  at  the  outset  of  a  fresh 
rotation,  to  restore  a  field  to  its  former  fertility  ;  and  it 
is  not  difficult  to  see  that  this  quantity  must  always  be 
proportionate  to  the  effective  dung-constituents  already 
present  in  the  soil ;  a  field  largely  abounding  in  them 
takes  less  manure  than  a  poor  field  to  give  the  same 
increased  produce. 

Now,  as  farm-yard  manure  owes  its  most  active 


THE    SYSTEM   OF   FARM-YAKD   MANURING. 

constituents  to  clover,  turnips,  and  the  grasses,  the  in- 
ference is  pretty  clear  that  the  quantity  of  this  manure 
required  on  a  lield  is  in  an  inverse  ratio  to  the  produce 
of  clover,  turnips,  or  grass,  which  the  field  can  give 
when  unmanured. 

The  Saxon  experiments  show  that  this  inference 
cannot  be  far  from  the  truth,  in  one  respect  at  least ; 
for  on  comparing  the  produce  of  clover  given  by  the 
unmanured  plots  with  the  quantity  of  farm-yard 
manure  applied,  we  find : — 

Clover  crops  in  1854. 

Cunnersdorf.       Mausegast.       KStitz.        Oberbobritzsch.    Oberschona. 
Pounds..   9144  6583  1095  911 

Quantity  of  manure  applied  in  1851. 
Cwt 180  194  229  314  897 

The  field  at  Cunnersdorf  which  contained  the  largest 
store  of  dung-constituents  received  the  smallest;  the 
field  at  Oberbobritzsch  which  gave  the  smallest  crop 
of  clover,  the  largest  quantity  of  farm-yard  manure. 

The  crop  of  clover,  however,  is  not  the  only  factor 
to  determine  the  amount  of  farm-yard  dung  required 
for  manuring  ;  for  one  of  the  clover-constituents,  silicic 
acid,  which  is  indispensable  to  the  cereal  plants,  is 
present  only  in  trifling  proportion,  and  hence  the  quan- 
tity of  farm-yard  manure  (straw-manure)  must  bear  a 
definite  ratio  to  the  quantity  of  straw-constituents 
already  present  in  the  ground. 

If,  in  the  Saxon  experiments,  we  compare  the  in- 
creased produce  of  corn  and  straw  obtained  from  the 
fields  manured  with  farm-yard  dung,  we  find  : — 

Increase  of  produce  by  farm-yard  manuring,  per  acre. 

Cunnersdorf.         Kotitz.  Oberbobritzsch. 

Quantity  of  farm-yard  manure 180  cwt.  229  cwt.         314  cwt. 

Corn  347  Ibs.  352  Ibs.          452  Ibs. 

Straw :. 1743    u  1006    "  914   " 

The  field  in  Cunnersdorf,  manifestly  the  richest  in 
substances  nutritive  for  straw,  gave  the  largest  straw- 


RATIONAL    SYSTEM   OF   FARMING.  213 

crop,  although  it  had  received  the  smallest  quantity  of 
farm-yard  manure.  In  the  increased  produce,  corn  was 
to  straw  as  1  :  5,  clearly  showing  that  sparing  applica- 
tion of  straw  manure  was  the  proper  course  to  pursue 
here.  This  fact  readily  explains  also  why  the  lield  at 
Oberbobritzsch,  comparatively  poorer  in  straw-constitu- 
ents, required  85  cwt.  of  farm-yard  manure  more  than 
the  Kotitz  field,  to  enable  it  to  maintain,  in  its  in- 
creased produce,  the  same  proportion  of  corn  and  straw 
(1  :  2)  as  in  the  crop  from  the  unmanured  plot. 

These  considerations  might,  perhaps,  lead  the  prac- 
tical farmer  to  the  conviction  that  he  is,  after  all,  not 
much  of  a  free  agent  in  the  cultivation  of  his  fields,  and 
that  the  '  facts  and  circumstances '  which  guide  him  in 
his  proceedings  are  simply  laws  of  nature,  of  whose 
existence  he  has  scarcely  any  conception.  In  truth,  it 
may  be  said  that  the  agriculturist  is  a  free  agent  only 
in  his  wrong-doings.  If  he  acts  in  accordance  with  his 
own  interest,  he  must  allow  himself  to  be  guided,  even 
though  unconsciously,  by  the  condition  of  his  land ;  and 
the  only  matter  for  wonder  is,  how  far  the  man  of '  ex- 
perience '  has  succeeded  in  this  way. 

A  system  of  farming,  to  be  called  truly  rational, 
must  be  exactly  suited  to  the  nature  and  condition  of 
the  soil ;  for  it  is  only  when  the  rotation  of  crops  or  the 
mode  of  manuring  is  conformable  to  the  composition  of 
the  soil,  that  the  farmer  has  a  sure  prospect  of  realising 
the  highest  possible  returns  from  his  labour  or  from  the 
capital  invested. 

Now  considering,  for  instance,  the  great  difference 
in  the  condition  of  the  soil  at  Cunnersdorf  and  Ober- 
bobritzsch, it  is  self-evident  that  the  same  rotation  of 
crops  which  suits  the  one  field,  will  not  answer  equally 
well  for  the  other. 

If  farmers  would  only  make  up  their  minds  to  ac- 
quire by  experiments  on  a  small  scale,*  an  accurate 
knowledge  of*  the  productive  power  of  their  land  for 
certain  kinds  or  classes  of  plants,  a  few  more  experi- 

*  In  a  field  of  pretty  uniform  composition,  experiments  of  this  kind 
may  be  made  with  flower  pots  sunk  in  the  earth. 


214  THE   SYSTEM   OF  FARM- YARD   MANURING. 

ments  would  readily  enable  them  to  discover  what 
nutritive  substances  their  land  contains  in  minimum 
proportion,  and  what  manuring  agents  ought  to  be  ap- 
plied to  ensure  the  production  of  a  maximum  crop. 

In  matters  of  this  kind  the  farmer  must  pursue  his 
own  course,  and  the  proper  course  is  -the  one  that  will 
most  fully  secure  the  object  he  has  in  view ;  he  must 
not  put  the  least  faith  in  the  assertion  of  any  foolish 
chemist,  who  wants  to  prove  to  him  analytically  that 
his  field  contains  an  inexhaustible  store  of  this  or  that 
nutritive  substance.  For  the  fertility  of  a  field  is  not 
proportionate  to  the  quantity  of  one  or  several  food 
elements  analytically  shown  to  exist  in  it,  but  to  that 
fraction  of  the  total  nutritive  substances  which  the  field 
is  able  to  give  up  to  the  plants ;  and  the  only  means  of 
determining  that  fraction  is  by  the  plant  itself.  The 
most  that  chemical  analysis  can  do  is  to  supply  a  few 
data  for  comparing  the  condition  of  two  fields.  The 
experiments  made  by  the  beet-root  growers  on  the  ex- 
tensive tract  of  land  in  Russia,  known  as  the  Tscherno- 
sem  or  '  Black  soil,'  whose  fertility  for  corn  plants  is 
proverbial,  show  that  this  earth,  though  analytically 
proved  to  contain  upon  the  whole,  to  the  depth  of 
twenty  inches,  TOO  to  1000  times  the  quantity  of  potash 
required  for  a  full  beet-root  crop,  is,  after  three  or  four 
years'  cultivation,  so  exhausted,  that  without  manuring 
it  will  no  longer  yield  a  remunerative  crop  of  beetroot.* 

In  the  produce  of  cereals  there  is  only  one  proper 
proportion  between  grain  and  straw ;  but  the  unfavour- 
» 

*  With  regard  to  the  general  opinion  about  the  abundance  and  inex- 
haustibility of  potash  in  land,  the  following  announcement,  in  the  '  Badische 
Centralblatt  fiir  Staats  und  Gemeinde-Interessen,'  May  1861,  is  not  without 
interest.  '  In  the  District  of  Bretten. — The  contracts  which  usually  take 
place  in  the  early  part  of  the  year  for  the  cultivation  of  beetroot,  are  now 
fully  open  for  competition  in  this  district,  and  for  good  articles  30  francs 
the  cwt.  are  offered  this  year,  whereas  last  year  only  26  francs  were  paid. 
Notwithstanding  this  rise  of  prices,  and  the  premiums  offered  for  superior 
roots,  not  many  transactions  have  been  concluded.  The  reason  of  this  is 
quite  intelligible,  for  the  very  injurious  effects  resulting  to  land  on  which 
this  product  has  been  cultivated,  are  too  well  known.'  The  effects  must 
have  reference  to  fields  which  had  been  adequately  manured,  for  otherwise 
no  profitable  returns  can  be  expected. 


PERMEABILITY   OF    SOILS    TO    MANURES.  215 

able  proportions  are  many.  It  is  clear  that  the  mass 
and  extent  of  the  organs  for  the  formation  of  grain  (in 
other  words,  the  bulk  of  the  straw)  must  bear  a  definite 
relation  to  the  product,  that  is,  to  the  quantity  of  grain 
produced:  any  excess  or  deficiency  in  the  amount  of 
straw  must  always  act  injuriously  upon  the  grain  crop. 

When  it  is  known  that,  on  a  given  field,  one  part 
by  weight  of  corn  to  two  parts  by  weight  of  straw  is 
the  most  favourable  proportion  for  the  production  of 
grain,  then,  according  to  theory,  the  manuring  of  the 
field  should  not  be  such  as  to  cause  any  marked  altera- 
tion of  this  relative  proportion  in  the  increased  prod- 
iice;  that  is  to  say,  the  several  manuring  substances 
should  be  selected  and  laid  upon  the  field  in  such  quan- 
tity and  relative  proportion,  that  the  composition  of 
the  soil  may  remain  the  same  as  it  was  before. 

It  is  well  known  that  certain  manuring  substances  are 
especially  favourable  to  the  formation  of  the  herbaceous 
parts  of  plants,  others  to  that  of  seed.  Phosphates,  as  a 
general  rule,  increase  the  grain  crop  :  whilst  of  gypsum 
it  is  well  known  that  where  that  substance  effects  an 
increase  in  the  produce  of  clover-hay,  this  increase  is 
always  attended  with  a  marked  diminution  in  the  prod- 
uce of  seed.  The  cultivation  of  potatoes  or  Jerusalem 
artichokes  tends  to  reduce  the  excessive  accumulation 
in  the  arable  surface  soil,  of  substances  which  promote 
the  formation  of  the  herbaceous  parts  of  plants. 
Theoretically,  therefore,  it  is  not  impossible  to  main- 
tain a  certain  uniformity  of  composition  in  the  soil  of  a 
field ;  but  this  cannot  be  effected  by  carrying  pn  the 
husbandry  of  an  estate  by  the  system  of  farm-yard 
manuring.  It  will  hereafter  be  shown  that  by  the  con- 
tinuous and  exclusive  use  of  farm-yard  manure,  the 
composition  of  the  soil  is  found  changed  after  each 
rotation. 

The  last  point  which  claims  our  attention,  in  refer- 
ence to  the  Saxon  experiments,  is  the  difference  in  the 
permeability  of  the  soil  to  the  dung-constituents  in  the 
different  localities.  The  depth  to  which  the  alkalies, 
the  ammonia,  and  the  soluble  phosphates  penetrate, 


216  THE   SYSTEM   OF   FARM-YAKD   MANURING. 

depends  of  course  upon  the  absorptive  power  of  the 
soil ;  now,  assuming,  for  the  sake  of  illustration,  the  soil 
of  a  field  to  be  divided  from  the  top  downwards  into 
distinct  layers,  which  are  not  of  course  sharply  sepa- 
rated from  one  another,  we  find  that  in  some  localities 
the  dung-constituents  stop  in  the  upper  layers,  whilst 
in  others  they  penetrate  to  the  deeper  layers  of  the 
ground.  Thus,  for  instance,  in  the  Cunnersdorf  field 
the  clover  crop  had  derived  no1  benefit  from  the  farm- 
yard manure,  being  about  only  4  per  cent,  larger  than 
the  produce  given  by  the  urimanured  plot ;  whereas 
at  Mausegast  the  manuring  caused  an  increase  of  30 
per  cent.,  and  at  Oberbobritzsch  of  200  per  cent.  This 
result  shows  that  certain  mineral  constituents,  indispen- 
sable for  clover,  penetrated  much  deeper  into  the 
ground  at  Mausegast  and  Oberbobritzsch  than  at  Cun- 
nersdorf and  Kotitz  ;  or,  what  comes  to  the  same,  that, 
in  the  two  latter  places,  they  were,  on  their  way  down- 
wards, retained  by  the  upper  layer  of  the  soil.  On 
comparing  the  crops  given  by  the  unmanured  plot  at 
Cunnersdorf  with  those  obtained  from  the  unmanured 
plots  in  the  other  localities,  we  see  that  the  Cunners- 
dorf field  contained  nearly  as  large  a  store  of  straw 
constituents  as  the  fields  at  Kptitz  and  Oberbobritzsch, 
while  it  was  decidedly  poorer  in  the  principal  grain 
constituents,  namely,  in  phosphoric  acid  and,  perhaps, 
also  in  nitrogen.  Hence,  with  an  equal  supply  of 
phosphates  and  ammonia  on  the  three  fields,  the  top- 
most layer  of  the  ground  at  Cunnersdorf,  being  poorer 
in  these  constituents,  would  retain  a  great  deal  more 
of  them  than  that  of  the  other  two  fields. 

The  increase  in  the  potato  crop  and  in  the  produce 
of  oat-grain  and  straw,  on  the  Cunnersdorf  field,  clearly 
indicates  that  certain  dung-constituents  made  their  way 
to  that  layer  of  the  soil  from  which  the  roots  of  the  oat- 
plant  principally  derive  their  food,  which  layer,  being 
richer  in  corn  and  straw  constituents  than  the  arable 
surface  soil,  permitted  a  small  proportion  of  nutritive 
substances  to  pass  through  it  and  thus  reach  the  clover. 

If  we  compare  with  this  the  field  at  Kotitz,  and  look 


COMPARISON   OF  RESULTS   IN   AGRICULTURE.          217 

at  its  extraordinarily  scanty  crop  of  oat-grain  and  straw, 
we  see  at  once  that  in  the  latter  field  the  deeper  layers 
of  the  soil  were  ranch  poorer  in  corn  and  straw  con- 
stituents, but  that  the  topmost  layer  was  much  richer 
in  corn  constituents  than  the  land  at  Ounnersdorf. 

Although  the  Kotitz  field  received  above  25  per 
cent,  more  farm-yard  manure  than  the  Cunnersdorf 
field,  yet  only  a  very  insignificant  portion  of  that 
manure  found  its  way  down  to  the  clover,  as  the  layer 
above  had  retained  the  substances  nutritive  to  clover, 
and  these  had  principally  served  to  benefit  the  oat- 
plant.  The  increase  in  the  produce  of  oat-grain  at 
Kotitz  was  more  than  double  that  obtained  from  the 
Cunnersdorf  field.  At  Mausegast  the  relations  were 
similar ;  from  the  uncommon  abundance  of  corn  and 
straw  constituents  in  the  arable  surface  soil,  the  absorp- 
tive or  retentive  power  of  the  latter  for  the  dung-con- 
stituents in  solution  was  comparatively  less,  and  a  con- 
siderable proportion  of  these  substances  was  thus  per- 
mitted to  reach  the  deepest  layers.  The  uniform  rise 
of  the  successive  crops  obtained  from  the  manured  field 
at  Oberbobritzsch  evidently  shows  a  very  uniform  dis- 
tribution of  active  dung-constituents,  such  as  might  be 
expected  in  a  soil  which,  though  not  exactly  sandy,  yet 
contained  a  larger  proportion  of  sand  than  any  of  the 
other  experimental  fields. 

It  is  easy  to  see,  that  by  knowing  the  absorptive 
power  of  the  arable  soil  in  these  several  fields,  the 
farmer  is  enabled  to  determine  beforehand  to  what 
depth  the  nutritive  substances  supplied  in  the  manure 
will  penetrate  into  the  ground ;  and  it  follows,  as  a 
matter  of  course,  that  he  is  able  to  apply  with  greater 
effect  the  mechanical  means  at  his  disposal  for  promot- 
ing the  distribution  of  these  elements  in  the  soil,  in  the 
right  places  and  in  the  proper  manner. 

It  would  answer  no  good  purpose  to  expatiate  still 
further  on  this  point ;  my  object  has  been  to  direct  the 
attention  of  the  farmer  to  the  different  facts  or  phenom- 
ena which  are  presented  by  his  land  during  the  process 
of  cultivation;  because  a  closer  observation  of  each 
10 


218  THE    SYSTEM    OF   FARM- YARD   MANURING. 

phenomenon  will  lead  him  to  reflect  upon  the  cause  of 
it.  This  is  the  way  to  obtain  an  accurate  knowledge  of 
the  state  and  condition  of  the  soil. 

Observation  and  reflection  are  the  fundamental  con- 
ditions of  all  progress  in  natural  science ;  and  agricul- 
ture presents,  in  this  respect,  ample  room  for  discov- 
eries. What  must  be  the  feelings  of  happiness  and 
contentment  of  the  man  who,  by  skilfully  turning  to 
proper  account  his  intimate  knowledge  of  the  peculiari- 
ties of  his  land,  has  succeeded,  without  increased  appli- 
cation of  labour  or  capital,  in  gaining  from  it  a  perma- 
nent increase  of  produce  ?  For  such  a  result  is  not 
only  a  personal  advantage  to  himself,  but  a  most  im- 
portant benefit  conferred  upon  all  mankind. 

How  paltry  and  insignificant  do  all  our  discoveries 
and  inventions  appear,  compared  to  what  is  in  the 
power  of  the  agriculturist  to  achieve ! 

All  our  advances  in  arts  and  sciences  are  of  no 
avail  in  increasing  the  conditions  of  human  existence ; 
and  though  a  small  fraction  of  society  may  by  their 
means  be  gainers  in  material  and  intellectual  enjoyment, 
the  load  of  misery  weighing  upon  the  great  mass  of  the 
people  remains  the  same.  A  hungry  man  cares  not  for 
preaching,  and  a  child  that  is  to  learn  anything  at 
school  must  not  be  sent  there  with  an  empty  stomach. 

Every  step  in  advance,  however,  'made  by  agricul- 
ture serves  to  alleviate  the  sufferings  and  troubles  of 
mankind,  and  to  make  the  human  mind  susceptible  and 
capable  of  appreciating  the  good  and  the  beautiful 
that  art  and  science  present  to  us.  Improvements  in 
agriculture  constitute  the  only  solid  foundation  for  fur- 
ther progress  in  all  other  branches  of  knowledge. 

We  now  proceed  to  consider  the  changes  brought 
about  in  the  composition  of  the  soil  of  a  given  field  by 
cultivation  by  the  system  of  farm-yard  manuring.  The 
cause  to  which  the  restoration  of  the  power  of  produc- 
tion in  the  soil  by  farm-yard  manure  is  attributable,  is 
the  same  in  the  case  of  all  soils,  without  exception, 
however  widely  the  rotations  may  differ,  or  whatever 
be  the  nature  of  the  crops  cultivated  upon  them. 


MINERAL   MATTERS    RESTORED   BY    MANURE. 

By  the  cultivation  of  cereals,  and  the  removal  of  the 
corn-crops,  the  arable  surface  soil  loses  a  certain  por- 
tion of  corn-constituents,  which  must  be  restored  to  it 
by  farm-yard  manure,  if  the  future  crops  are  to  be  kept 
up  to  the  mark  of  the  preceding  ones. 

This  restoration  is  effected  by  the  cultivation  of  fod- 
der-plants, such  as  turnips,  clover,  grass,  &c.,  on  which 
the  cattle  on  the  farm  are  fed,  and  the  constituents  of 
which  are  drawn,  in  large  proportion,  from  the  deeper 
layers  of  the  ground,  where  the  roots  of  the  cereals 
cannot  penetrate. 

These  fodder  plants  are  consumed  either  on  the  field 
itself,  as  turnips  in  England,  or  in  the  stalls.  A  frac- 
tion of  the  nutritive  substances  contained  in  these 
plants  remains  in  the  body  of  the  animals  fed  upon 
them,  while  the  remainder,  ejected  in  the  form  of  solid 
or  liquid  excrements,  constitutes  farm-yard  manure,  the 
principal  bulk  of  which,  however,  consists  of  straw 
which  has  served  for  litter. 

In  Germany  animals  are  not  fed  upon  potatoes 
themselves,  but  upon  the  refuse  from  the  distilleries  of 
potato  spirits,  which  contains  all  the  nutritive  substances 
taken  away  from  the  soil  in  the  potato  crop,  together 
with  the  constituents  of  the  barley-malt  that  have 
been  used  in  the  process  of  mashing. 

Since  the  whole  of  the  straw  taken  away  in  the 
crops  of  the  preceding  rotation  is,  as  a  general  rule, 
returned  to  the  arable  soil  in  the  shape  of  farm-yard 
manure,  the  field  is,  at  the  outset  of  the  new  rotation, 
as  rich  as  before  in  the  conditions  for  the  production  of 
straw ;  and  there  exists,  under  these  circumstances,  no 
ground  for  a  diminution  of  the  straw-crops. 

With  regard  to  the  clover,  turnips,  potato- waste, 
&c.,  upon  which  the  stock  on  a  farm  is  fed,  there  re- 
mains, as  already  stated,  in  the  bodies  of  the  horses, 
cattle,  &c.,  and  full-grown  animals  in  general  (which 
no  longer  materially  increase  in  weight),  only  a  very 
small  fraction  of  the  constituents  of  the  food  consumed ; 
but  in  the  young  cattle  sent  to  market,  in  the  bodies  of 
the  sheep,  in  the  milk  and  cheese,  a  portion  of  these 


220  THE   SYSTEM   OF  FABM-YAKD   MANURING. 

constituents  is  retained,  which  is  not  returned  to  the 
soil  in  the  farm-yard  manure.  The  loss  of  phosphoric 
acid  and  potash  which  the  soil  sustains  by  the  sale  of 
cattle  and  of  animal  products  (wool,  cheese,  &c.),  may 
be  estimated  at  one-tenth  of  the  quantity  of  these  min- 
eral constituents  contained  in  the  potatoes,  turnips,  or 
clover ;  and  even  this  estimate  is,  perhaps,  too  high. 
At  all  events,  it  is  risking  no  great  error  to  assume 
that  nine-tenths  of  all  the  constituents  of  the  clover, 
potatoes,  or  turnips,  are  returned  to  the  field  in  the 
farm-yard  manure;  whence  the  arable  surface  soil, 
after  manuring,  is  richer  for  the  new  rotation  in  the 
mineral  constituents  of  potatoes,  clover,  and  turnips, 
than  it  was  before,  as  the  constituents  of  the  two  latter 
plants  have  been  brought  up  from  the  deeper  layers  of 
the  ground. 

The  far  greater  portion  of  the  active  dung-constitu- 
ents is  retained  by  the  upper  layers  of  the  soil,  the 
deeper  layers  getting  back  very  little  of  what  has  been 
taken  from  them ;  the  power  of  the  latter,  therefore,  to 
produce  as  large  crops  of  clover  or  turnips  as  before  is 
not  restored. 

The  soil  constituents  which  the  animals  have  derived 
from  the  turnips,  clover,  potatoes,  &c.,  and  which  re- 
main in  their  bodies,  are  very  nearly  identical,  in 
quantity  and  quality,  with  those  of  the  cereals ;  hence 
the  loss  sustained  by  the  land  may  be  estimated  as 
equal  to  the  corn-crops  sold,  plus  the  corn-constituents 
which  the  fodder-plants  have  given  up  to  the  animals 
on  the  farm. 

The  restoration  of  the  power  of  a  field  to  produce  a 
crop  of  corn  as  large  as  the  last  naturally  presupposes 
that  the  conditions  required  for  the  production  of  the 
new  crop  should  remain  the  same  in  the  very  layer  of 
the  soil  which  supplied  the  preceding  crop ;  in  other 
words,  the  substances  nutritive  to  corn  which  were 
taken  away  must  be  fully  returned  to  the  arable  surface 
soil. 

If  farm-yard  manure  contained  only  the  constituents 
of  straw  and  potatoes,  and  nothing  else,  manuring  a 


THE   ELEMENTS   OF   FOOD   IN   FABM-YAKD   MANURE.       221 

field  with  it  could  merely  restore  the  productive  power 
of  the  arable  soil  for  straw  and  potatoes,  but  not  for 
corn.  Under  these  circumstances  it  would  remain  as 
rich  as  before  in  food  elements  for  straw  and  potatoes, 
but  would  be  poorer  for  corn  to  the  extent  of  the  whole 
quantity  of  corn-constituents  taken  away  in  the  crops. 

If  farm-yard  manure  is  to  restore  the  former  produc- 
tiveness of  a  field  for  corn,  it  must  necessarily  contain 
an  amount  of  corn-constituents  corresponding  to  the 
loss  sustained,  that  is  to  say,  as  much  or  even  more 
than  has  been  removed. 

The  amount  of  the  elements  of  food  for  corn  con- 
tained in  the  farm-yard  manure  naturally  depends  upon 
the  sum  of  these  elements  which  have  passed  over  into 
manure,  from  the  cattle  feeding  upon  clover  or  turnips. 

Where  this  supply  exceeds  the  loss  sustained,  the 
arable  soil  is  actually  made  richer  in  corn-constituents  ; 
but  in  that  case  it  is  enriched  also  in  the  conditions  for 
an  increased  produce  of  straw  and  tuberous  plants. 
Where,  therefore,  the  farm-yard  manure  (by  the  clover 
or  turnip  constituents  in  it)  increases  the  amount  of 
phosphoric  acid  and  nitrogen  in  the  arable  soil,  it  in- 
creases, in  a  much  greater  proportion,  the  quantity  of 
potash  and  lime,  and  to  some  extent  also  that  of  silicic 
acid ;  and  since,  as  already  stated,  the  whole  of  the 
straw-constituents  removed  from  the  field  are  brought 
back  to  it  in  that  manure,  higher  crops  of  corn,  straw, 
and  potatoes  are  the  natural  result. 

This  increase  of  the  produce  of  all  cultivated  plants 
drawing  their  principal  food  from  the  arable  surface 
soil,  may  go  on  for  a  very  long  time,  but  in  all  fields 
it  has  a  certain  appointed  limit. 

The  time  comes,  sooner  or  later,  for  every  field, 
when  the  subsoil  (which  is  to  the  clover  or  turnips 
what  the  arable  surface  soil  is  to  the  cereals),  suffering 
a  continued  drain  upon  its  stores  of  phosphoric  acid, 
potash,  lime,  magnesia,  &c.,  begins  to  lose  its  produc- 
tive power  for  clover  or  turnips ;  and  thus  the  nutritive 
substances,  taken  away  from  the  arable  surface  soil  in 
the  corn  crops,  are  no  longer  replaced  from  the  store 


222  THE   SYSTEM  OF  FARM-YAftD  MANURING. 

which  existed  in  the  deeper  layers,  and  was  brought  up 
by  the  clover  or  the  turnips.  But  the  high  returns  of 
corn  given  by  a  field  do  not  necessarily  decline  with  the 
incipient  failure  of  the  clover ;  for  where  the  arable 
soil  of  a  field  has,  after  every  rotation,  received  from  the 
clover  or  turnips  more  corn-constituents  than  it  had 
lost  by  the  corn-crop,  there  may  be  a  gradual  accumu- 
lation of  an  excess  of  these  elements  of  food  sufficient  to 
conceal  altogether  from  the  farmer  the  true  condition  of 
his  land.  By  introducing  into  his  rotation  vetches,  white- 
clover,  and  other  fodder-plants  that  derive  their  food 
from  the  upper  layers  of  the  soil,  he  succeeds  in  keeping 
up  his  live  stock,  and  he  indulges  in  the  notion  that  all 
things  go  on  in  his  field  just  as  before,  when  the  clover 
or  the  turnips  yielded  good  crops.  This  is  of  course 
simply  a  delusion,  as  there  is  no  longer  an  actual  re- 
placement of  the  loss  sustained.  His  high  corn-crops 
are  now  gained  at  the  expense  of  the  nutritive  sub- 
stances accumulated  in  excess  in  the  arable  surface  soil 
which  are  set  in  motion  by  the  fodder-plants  introduced 
into  the  rotation,  and  are  uniformly  distributed  again 
in  the  arable  soil  after  each  rotation,  by  means  of  the 
farm-yard  manure. 

His  dung-heap  may  happen  to  be  of  larger  bulk  and 
extent  than  formerly,  but  as  the-re  is  now  no  further 
supply  of  nutritive  substances  brought  up  from  the  sub- 
soil or  the  deeper  layers  by  the  clover  or  turnips,  the 
power  of  the  manure  to  restore  the  original  fertility  of 
the  arable  soil  is  continually  decreasing  With  the 
ultimate  consumption  of  the  excess  of  corn-constituents 
accumulated  in  the  arable  soil,  the  time  comes  when 
the  corn-crop  begins  to  diminish,  whereas  the  produce 
of  straw  is  comparatively  higher  than  before,  as  the 
conditions  for  the  formation  of  straw  have  been  steadily 
increasing. 

Of  course,  the  farmer  cannot  fail  to  remark  the 
diminution  of  his  corn-crops,  which  induces  him  to  have 
recourse  to  drainage,  to  improved  tillage,  and  to  the 
substitution  of  other  cultivated  plants,  in  lieu  of  clover 
and  turnips.  If  the  subsoil  of  his  fields  will  permit  it, 


RESULTS   OF   FARM-YARD   MANURING.  223 

he  now  includes  in  his  rotation  lucerne  and  sainfoin, 
whose  still  longer  and  more  widely  spreading  roots 
enable  them  to  reach  yet  deeper  layers  of  the  ground 
than  the  red  clover ;  until  finally  he  employs  the  yel- 
low lupine,  which  may  truly  be  called  the  '  hunger- 
plant.' 

A  new  increase  of  produce  is  the  result  of  these  '  im- 
provements '  in  his  system  of  cultivation  by  farm-yard 
manuring,  which  the  farmer  looks  upon  as  a  great  ad- 
vance. A  fresh  store  of  nutritive  substances,  brought 
up  from  the  deeper  layers  of  the  soil,  may  possibly  ac- 
cumulate again  in  the  arable  surface  soil ;  but  these 
deeper  layers  also  will  be  gradually  exhausted,  and  the 
accumulated  store  in  the  arable  surface  soil  will  also  be 
consumed. 

This  is  the  natural  termination  of  cultivation  l)y  the 
system  of  farm-yard  manuring. 

The  fields  of  the  Saxon  experiments  afford  very  fair 
illustrations  of  the  different  conditions  to  which  arable 
land  in  general  is  brought,  by  a  pure  system  of  farm- 
yard manuring. 

The  field  at  Cunnersdorf  is  in  the  first  stage,  the 
Mausegast  field  in  the  second,  the  fields  at  Kotitz  and 
Oberbobritzsch  in  the  third  stage,  of  cultivation  by 
farm-yard  manuring,  to  which  we  have  referred. 

At  Cunnersdorf  the  arable  soil  exhausted  by  the 
preceding  cultivation  becomes  with  every  new  rotation 
richer  in  the  conditions  required  for  the  production  of 
grain ;  not  only  does  the  clover  replace  the  loss  sus- 
tained by  the  removal  of  the  corn-crops,  but  a  remark- 
able excess  of  all  nutritive  substances  will  gradually 
accumulate  in  the  arable  soil ;  and,  after  a  series  of 
years,  with  the  same  system  of  cultivation  by  farm-yard 
manuring,  the  field  will  be  brought  to  the  condition  of 
the  land  at  Mausegast ;  which  means,  that  the  arable 
soil  will  acquire  a  high  productive  power  for  corn  and 
other  crops,  while  the  produce  of  clover  will  decrease. 
The  fields  at  Kotitz  and  Oberbobritzsch  most  probably 
were  in  former  times  in  the  same  condition  as  the  Mau- 
segast field  is  .at  present ;  not  that  they  ever  yielded 


224  THE   SYSTEM   OF  FAEM-YAED  MANTJEING. 

crops  as  large  as  the  latter  gives,  but  merely  that  the 
unmanured  plots  have,  at  some  antecedent  period,  given 
better  crops  than  in  the  year  1851.  Without  an  addi- 
tional supply  of  niineral  elements  derived  from  mea- 
dows or  other  fields  not  included  in  the  rotation,  the 
produce  must  go  on  continually  decreasing,  as  the  sup- 
ply of  mineral  constituents  brought  up  by  the  clover 
from  the  subsoil,  in  these  two  places,  is  far  from  suf- 
ficient to  make  up  for  what  is  taken  away  in  the  corn- 
crops. 

In  the  following  calculation  it  has  been  assumed 
that  of  the  crops  obtained,  rye  and  oats  were  actually 
removed,  and  of  potatoes  and  clover  one-tenth  was  car- 
ried away  in  the  form  of  cattle.* 

Cunnersdorf. 

Phosphoric  acid.     Potash. 
Ibs.  Ibs.  Ibs. 

The  arable  soil  lost  by  removal  of  1176  rye-grain. .  10'2  5 -5 

2019  oats 15-3  7'7 

"                            "                   -j1},-  potato  crop  2'3  l*lf 

"                            "                   fo  clover  crop  4'0  2'0f 

Total  loss 31-8  16'3 

The  arable  soil  had  returned  to  it,  in  -&  of  9144  Ibs. 

of  clover-hay    36*18  95'5 

Balance  in  excess  .  4-38  79-2 


The  arable  soil  of  the  Cunnersdorf  field  received, 
accordingly,  in  the  farm-yard  manure,  more  phosphoric 
acid  and  more  potash  than  had  been  carried  off  by  the 
corn-crops. 

In  this  calculation,  it  is  a  question  of  no  importance 
how  much  of  the  rye  or  oats  was  carried  off.  More 

*  The  amount  of  phosphoric  acid  and  potash  is  estimated  in  the  cal- 
culation as  follows : — 

Eye  Oats  Potatoes.  Clover-hay. 

Corn.     Straw.        Corn.    Stra\v. 

Phosphoric  acid 0'864     0'12         0-75     0'12         0'14         0'44 

Potash 0'47       0'52         0-38     0'94         0'58         1-16 

j-  The  quantity  of  potash  is  calculated  here  upon  the  proportion  of 
phosphoric  acid  in  corn,  one  part  by  weight  of  potash  to  two  parts  by 
weight  of  phosphoric  acid. 


MINERAL  MATTEES   LOST  IN   CROPS.  225 

than  the  field  produced  could  not  be  carried  away,  and 
if  less  were  removed  the  only  effect  would  be  that  phos- 
phoric acid  and  potash  would  accumulate  all  the  more 
in  the  field. 

Mausegast. 

Phosphoric  acid.  Potash. 

Ibs.  IbB. 
The  arable  soil  lost  by  the  rye-grain,  barley-grain,  • 

-fa  potatoes,  fo  clover 35'4  18'1 

The  arable  soil  received  in  -,%  of  the  clover  crop  . .     22  0  62'0 

Loss 13-4     Gain  43-9 

Kotitz. 

Phosphoric  acid.  Potash. 

Ibs.  Ibs. 
The  arable  soil  lost  in  the  rye,  oats,  and  in  the  -j^-  of 

the  potatoes  and  clover    26*4  12*7 

It  received  in  the  clover 8'5  11-0 

Loss  .  17-9  1-7 


The  calculation  is  about  the  same  for  the  field  at 
Oberbobritzsch  as  for  Kotitz.  While  the  arable  soil  at 
Mausegast,  in  consequence  of  the  large  clover  crops  pro- 
duced by  it,  still  continues  to  gain  in  potash,  the  corn- 
crops  are  gradually  reducing  the  rich  store  of  potash  in 
the  Kotitz  field. 

These  three  fields  show  the  effect  of  a  pure  system 
of  farm-yard  manuring,  from  which  is  excluded  all  sup- 
ply of  manure  extraneous  to  the  farm  itself. 

An  additional  supply  of  fodder  purchased  from 
other  farms,  or  hay  grown  on  natural  meadows,  answers 
the  same  purpose  as  an  additional  supply  of  manure. 

It  is  self-evident  that  we  cannot  give  more  farm-yard 
manure  to  a  field  than  it  produces,  unless  we  take  the 
constituents  of  the  manure  from  some  other  field,  which 
in  that  case  must  lose  just  as  much  as  the  former  field 
gains. 

If  we  direct  our  attention  to  manured  fields,  we  find 

that  they  give  larger  corn-crops,  and  in  many  cases  also 

larger  clover   or  turnip-crops ;    the  arable  soil  losing 

more  by  the  removal  of  the  corn-crop,  and  receiving 

10* 


226 


THE   SYSTEM  OF  FAKM-YAKD   MANURING. 


more  back  by  the  increased  produce  of  farm-yard  ma- 
nure, still  the  ultimate  results  remain  the  same. 

In  the  system  of  cultivating  by  rotation  of  crops,  it 
is  found  that,  for  a  long  time,  the  arable  soil  grows  with 
each  period  of  rotation  very  much  richer  than  it  is  by 
nature,  in  potash  as  well  as  in  lime,  magnesia  (the  prin- 
cipal constituents  of  clover  and  turnips),  and  in  silicic 
acid. 

These  substances  are  the  principal  conditions  for  the 
formation  of  roots  and  leaves ;  their  accumulation  in 
the  soil  tends  to  make  the  ground  rank  and  prone  to 
grow  weeds,*  as  the  farmer  says,  an  evil  which  arises 
as  a  necessary  consequence  from  cultivation  by  the  sys- 
tem of  farm-yard  manuring,  and  which  can  only  be 
met,  as  he  thinks,  by  a  rotation  of  crops. 

It  is  generally  supposed  that  the  best  remedy  is  the 
hoe  ;  but  though  mechanical  application  may  retard  the 
developement  of  weeds  for  a  time,  it  cannot  effectually 
prevent  them.  The  hoe  has  some  share  in  removing 
them,  but  not  all. 

*  The  most  noxious  of  these  weeds  are  the  wild  radish  (Raphanus 
raphanistrum\  the  corn  cockle  (Agrostemma  cithago),  the  corn-flower  or 
blue-bottle  (Centaurea  cyanus),  the  German  camomile  (Matricaria  chamo- 
milla),  and  the  corn  camomile  (Anthemis  arvensis).  All  these  plants  con- 
tain, in  their  ash,  as  much  potash  as  is  found  in  clover,  and  7  to  18  per 
cent,  of  chloride  of  potassium,  a  salt  which  forms  one  of  the  principal 
constituents  of  the  urine  of  animals,  and  which  is  brought  to  the  field  in 
the  farm-yard  manure. 


II. 

I. 

Matric. 

Matric. 

Anthemis 

Centaurea 

Agrostemma 

cham. 

cham. 

arvensis. 

cyanus. 

cithago. 

Per  cent,  ash     .... 

8-61 

9'69 

9-66 

7'32 

13-20 

The  ash  contains  : 

Potash  

25.49 

32-386 

30-5*7 

36'536 

22-86 

Chloride  of  potas- 

sium         . 

18*4 

14-25 

7-15 

11-88 

7-55 

Phosphoric  acid  .  . 

5-1 

7-80 

9-94 

6-59 

6-64 

Phosphate  of  iron 

2-39 

2-39 

4.77 

2-34 

1-80 

(RULING,  '  Annal.  d.  Chem.  und  Pharm.'  vol.  Ivi.  p.  122.) 


SUCCESSION   OF   CROPS    IN   ROTATION.  227 

The  succession  of  crops  in  rotation  is  always  made 
dependent  upon  the  cereals ;  the  preceding  crops  are 
selected  of  such  a  kind  that  their  cultivation  will  not 
injure,  but  rather  improve,  the  succeeding  corn-crop. 
The  selection  of  the  particular  kind,  however,  is  always 
governed  by  the  condition  of  the  soil. 

In  a  field  abounding  in  stalk  and  leaf  constituents, 
it  is  often  found  useful  to  have  wheat  preceded  by 
tobacco  or  rape,  rye  by  turnips  or  potatoes,  since  these 
plants  by  drawing  from  the  soil  a  large  amount  of  leaf 
and  stalk  constituents  serve  to  restore  a  more  suitable 
proportion  between  the  straw  and  corn  constituents  for 
the  future  cereal  crop,  and  at  the  same  time  to  diminish, 
in  the  arable  soil,  those  conditions  which  favour  the 
growth  of  weeds. 

The  preceding  observations  relative  to  the  produce 
given  by  the  Saxon  fields,  both  in  the  unmanured  and 
manured  state,  afford,  in  my  opinion,  a  perfect  insight 
into  the  nature  and  results  of  cultivation  by  the  system 
of  farm-yard  manuring.  In  the  condition  of  these  fields 
in  their  several  stages,  we  may  see  reflected  the  history 
of  agriculture. 

In  the  first  period,  or  on  a  virgin  soil,  corn-crop  is 
made  to  succeed  corn-crop,  and  when  the  produce  be- 

fins  to  fail,  the  culture  is  simply  transferred  to  a  fresh 
eld.  The  increasing  requirements  of  the  growing 
population,  however,  gradually  put  a  check  upon  this 
plan,  and  compel  a  steady  cultivation  of  the  same  sur- 
face ;  a  system  of  alternate  fallowing  is  now  resorted 
to,  and  efforts  are  made  to  restore  the  lost  fertility  of 
the  soil,  by  manuring  with  the  produce  of  the  natural 
meadows.  After  a  time,  this  expedient  begins  to  fail, 
and  leads  to  the  cultivation  of  fodder-plants,  the  sub- 
soil being  thus  turned  to  account  as  an  artificial  mead- 
ow. The  cultivation  of  fodder-plants  proceeds,  at  first, 
without  interruption ;  after  a  time,  longer  and  longer 
intervals  are  interposed  between  the  clover  and  turnip 
crops  ;  finally,  the  cultivation  of  fodder-plants  comes  to 
an  end,  and  with  it  the  system  of  cultivation  by  farm- 
yard manuring.  The  ultimate  result  is  the  absolute 


228  THE   SYSTEM  OF  FAEM-YAKD  MANURING. 

exhaustion  of  the  soil,  inasmuch  as  the  means  for  in- 
creasing the  produce  of  the  soil  gradually  pass  away 
from  it  by  this  system. 

Of  course,  the  progress  by  which  these  different 
stages  are  reached  is  extremely  slow,  and  the  results  are 
felt  only  by  the  third  and  fourth  generation.  When 
there  are  woods  near  the  arable  land,  the  peasant  seeks 
to  turn  the  fallen  leaves  to  account  as  manure ;  he 
breaks  up  the  natural  meadows  which  are  still  rich  in 
elements  of  food  for  plants,  and  converts  them  into 
arable  land  ;  then  he  proceeds  to  burn  down  the  forests, 
and  to  manure  his  fields  with  the  ashes.  When  the 
gradual  exhaustion  in  the  productive  power  of  the  land 
has  led  to  a  corresponding  decrease  in  the  population, 
the  peasant  cultivates  his  land  once  every  two  years 
as  in  Catalonia,  or  once  every  three  years  as  in  Andalu- 
sia.* 

No  intelligent  man  who  contemplates  the  present 
state  of  agriculture  with  an  unbiased  mind,  can  remain 
in  doubt,  even  for  a  moment,  as  to  the  stage  which  hus- 
bandry has  reached  in  Europe.  We  find  that  all  coun- 
tries and  regions  of  the  earth  where  man  has  omitted  to 
restore  to  the  land  the  conditions  of  its  continued  fer- 
tility, after  having  attained  the  culminating  period  of 
the  greatest  density  of  population,  fall  into  a  state  of 
barrenness  and  desolation.  Historians  are  wont  to 
attribute  the  decay  of  nations  to  political  events  and 
social  causes.  These  may,  indeed,  have  greatly  contrib- 
uted to  the  result ;  but  we  may  well  ask  whether  some 
far  deeper  cause,  not  so  easily  recognised  by  historians, 


*  The  Emperor  Charles  V.  gave  orders  that  the  meadows  recently 
turned  into  arable  land  should  be  restored  to  their  former  condition.  Even 
before  the  time  of  Charles  V.  orders  of  the  same  nature  had  been  issued  by 
the  first  Catholic  Kings,  and  at  a  still  earlier  period  by  Pedro  the  Cruel  of 
Castile.  In  the  beginning  of  the  fifteenth  century,  Henrique  of  Castile  pro- 
hibited the  exportation  of  cattle,  on  pain  of  death ;  and  as  early  as  the 
commencement  of  the  fourteenth  century,  King  Alonzo  Onzeno  had  issued 
ordinances  for  the  preservation  of  meadows  and  pastures.  ('  Bilder  aus 
Spanien  von  Karl  Freiherrn  von  Thienen,  Adlerflycht.'  Berlin :  Dunker, 
p.  241.)  All  in  vain  !  for  what  avails  the  power  of  even  the  mightiest 
monarchs  against  the  irrepressible  action  of  a  law  of  nature  ? 


FALSE   DOCTRINES.  229 

has  not  produced  these  events  in  the  lives  of  nations, 
and  whether  most  of  the  exterminating  wars  between 
different  races  may  not  have  sprung  from  the  inexorable 
law  of  self-preservation  ?  Nations,  like  men,  pass  from 
youth  to  age,  and  then  die  out — so  it  may  appear  to  the 
superficial  observer ;  but  if  we  look  at  the  matter  a 
little  more  closely,  we  shall  find  that,  as  the  conditions 
for  the  continuance  of  the  human  race  which  nature  has 
placed  in  the  ground  are  very  limited  and  readily 
exhausted,  the  nations  that  have  disappeared  from  the 
earth  have  dug  their  own  graves  by  not  knowing  how 
to  preserve  these  conditions.  Nations  (like  China  and 
Japan)  who  know  how  to  preserve  these  conditions  of 
life  do  not  die  out. 

Not  the  fertility  of  the  earth,  but  the  duration  of 
that  fertility,  lies  within  the  power  of  the  human  will. 
In  the  final  result,  it  comes  very  much  to  the  same 
thing,  whether  a  nation  gradually  declines  upon  a  soil 
constantly  diminishing  in  fertility,  or  whether,  being  a 
stronger  race,  it  maintains  its  own  existence  by  exter- 
minating and  taking  the  place  of  another  people  upon  a 
land  richer  in  the  conditions  of  life. 

It  can  hardly  be  ascribed  to  caprice  or  chance  that 
the  cultivator  in  the  huertas  of  Valencia  obtains  three 
crops  yearly  from  the  same  soil,  while  in  the  immediate 
neighbouring  district  the  ground  is  tilled  only  once  in 
three  years  ;  or  that  the  Spaniards  burned  down  forests 
in  sheer  ignorance,  in  order  to  use  the  ashes  to  restore 
the  fertility  of  their  fields.  (See  Appendix  G.) 

Everyone  who  is  at  all  acquainted  with  the  natural 
conditions  of  agriculture,  must  perceive  that  the  method 
of  culture  practised  for  centuries  in  most  countries  could 
not  but  inevitably  impoverish  and  exhaust  even  the 
most  fruitful  lands  ;  can  it  then  be  supposed  that  there 
will  be  any  exception  in  the  case  of  cultivated  lands 
in  Europe,  and  that  like  causes  will  not  produce  like 
effects  ? 

Under  these  circumstances,  is  it  right  or  reasonable 
to  pay  any  attention  to  the  doctrines  of  superficial  wise- 
acres, who,  with  their  wretched  chemical  analyses  find 


230  THE   SYSTEM   OF   FAKM-YAKD   MANUKING. 

an  inexhaustible  supply  of  nutritive  substances  in  any 
given  soil,  even  in  one  which  can  no  longer  produce 
clover,  turnips,  or  potatoes,  and  yet  may  be  rendered 
capable  of  producing  these  plants  by  manuring  with 
ashes  or  lime  in  the  right  places  ? 

In  the  face  of  the  daily  experience  which  shows  that 
the  corn-fields,  if  they  are  to  remain  fruitful,  must  be 
manured  after  a  short  series  of  years,  it  is  a  crime  against 
human  society,  a  sin  against  the  public  welfare,  to  dis- 
seminate the  doctrine  that  the  fodder-plants,  which  fur- 
nish manure  to  the  corn-fields,  will  constantly  find  upon 
the  field  the  conditions  of  their  own  growth,  that  the 
law  of  nature  applies  to  one  kind  of  plant  only,  and  has 
no  bearing  upon  the  other.  The  teaching  of  these  men 
has  no  other  result  than  to  keep  agriculture  in  the  low 
position  which  it  now  occupies.  In  England  it  is  a  mere 
mechanical  handicraft,  and  in  that  country  manure  is 
regarded  as  merely  the  oil  which  smoothes  the  wheels 
and  keeps  the  machine  in  motion. 

In  Germany  agriculture  is  a  jaded  horse,  treated 
with  blows  instead  of  fodder  ;  nowhere  is  its  real  beauty 
and  the  intellectual  aspect  of  its  pursuit  recognised. 
Not  merely  for  its  utility,  but  on  account  of  this  very 
intellectual  nature  of  its  pursuit,  it  stands  above  all 
occupations  ;  and  its  practice  procures,  to  the  man  who 
understands  the  voice  of  nature,  not  only  all  the  advan- 
tages for  which  he  strives,  but  also  those  pleasures  which 
science  alone  can  afford. 

In  human  society,  ignorance  is  undoubtedly  the 
fundamental,  and  therefore  the  very  greatest  evil.  The 
ignorant  man,  however  rich  he  may  be,  is  not  protected 
from  poverty  by  his  wealth  ;  while  the  poor  man,  who 
has  knowledge,  becomes  rich  by  its  means.  Uncon- 
sciously to  the  ignorant  farmer,  all  his  industry,  care, 
and  toil  only  hasten  his  ruin ;  his  crops  gradually  di- 
minish, and  at  length  his  children  and  grandchildren, 
no  wiser  than  himself,  are  unable  to  maintain  them- 
selves upon  the  homestead  where  they  were  born;  their 
land  passes  into  the  hands  of  the  man  who  has  knowl- 
edge; for  by  knowledge  capital  and  power  are  acquired, 


CORN    NOT   INCREASED    BY    FARM-YARD   MANURING.       231 

and  by  these,  as  a  matter  of  course,  the  helpless  are  ex- 
pelled from  the  inheritance  of  their  forefathers. 

As  an  animal  cannot  care  for  himself,  the  law  of 
nature  takes  care  of  him,  and  is  his  master  ;  but  not  so 
with  man,  who,  if  he  understands  the  intentions  of  God 
in  his  creation,  is  master  of  the  law  of  nature,  which 
yields  to  him  a  complete  and  willing  obedience.  The 
animal  brings  into  the  world  his  perceptions  and  in- 
stincts, which  grow  up  with  his  growth,  and  without 
any  effort  of  his  own ;  but  to  man  the  Creator  gave 
the  gift  of  reason,  and  this  distinguished  him  from  the 
brutes.  This  is  the  divine  talent,  which  he  should  put 
out  to  interest,  and  of  which  it  is  said,  '  He  that  hath, 
to  him  shall  be  given ;  but  from  him  that  hath  not, 
shall  be  taken  away  even  that  which  he  hath.'  It  is 
only  the  interest  procured  by  means  of  this  '  talent ' 
that  gives  man  power  over  the  forces  of  the  earth. 

Error  arising  from  want  of  knowledge  is  Excusable, 
for  no  one  adheres  to  it  after  recognising  its  existence  ; 
and  the  struggle  between  error  and  dawning  truth  arises 
from  the  natural  striving  of  men  for  knowledge.  In 
this  contest  truth  must  grow  stronger,  and  if  error  pre- 
vails, this  only  proves  that  truth  has  yet  to  grow,  not 
that  error  is  truth. 

At  all  times  the  '  better '  has  always  been  the  ene- 
my of  the  '  good  ; '  but  men  do  not  comprehend  for  all 
that  why,  in  so  many  cases,  ignorance  is  the  enemy  of 
reason. 

There  is  no  profession  which  for  its  successful  prac- 
tice requires  a  larger  extent  of  knowledge  than  agricul- 
ture, and  none  in  which  the  actual  ignorance  is  greater. 

The  farmer  who  practises  the  system  of  rotation, 
depending  exclusively  upon  the  application  of  farm-yard 
manure,  needs  very  little  observation,  nay  only  to  open 
his  eyes,  in  order  to  be  convinced,  by  innumerable  proofs, 
that  whatever  may  have  been  the  outlay  of  labour  and 
industry  applied  to  the  production  of  farm-yard  manure, 
his  fields  have  not  been  thereby  increased  in  the  power 
of  bearing  crops. 

If  farm-yard  manure  was  actually  able  to  render  a 


232  THE   SYSTEM   OF  FARM-YARD   MANURING. 

field  permanently  richer  in  nutritive  substances  than 
it  is  by  nature,  \ve  might  expect  that  a  course  of  manur- 
ing for  fifty  years  would  necessarily  produce  a  steady 
increase  in  the  crops. 

Now,  if  farmers  who  practise  the  system  of  rotation, 
laying  aside  all  bias  and  prejudice,  would  compare  their 
present  with  their  former  crops,  or  with  those  obtained 
by  their  fathers  or  grandfathers,  none  of  them  would 
be  able  to  say  that  the  crops  have  increased,  and  only 
few  that  the  average  has  remained  the  same.  Most  of 
them  would  find,  that  on  the  average,  the  straw-crops 
have  turned  out  higher,  but  the  corn-crops  lower,  and 
proportionately  lower  than  they  formerly  were  higher ; 
and  that  the  surplus  money  which  their  parents  gained 
by  the  former  high  crops,  the  result  of  their  improve- 
ments, as  they  supposed,  must  now  be  paid  out  again, 
to  purchase  manuring  substances,  which,  as  people 
formerly  thought,  could  be  *  produced.'  Now,  how- 
ever, they  begin  to  learn  that  though  such  substances 
may  be  produced  for  a  time,  they  cannot  be  reproduced 
in  perpetuity. 

In  like  manner,  the  farmer  whose  richer  ground  has 
enabled  him  to  carry  out  the  three-field  system,  and 
whose  rich  meadows  guarantee  a  supply  of  manure, 
who  obtains  as  abundant  harvests  and  as  large  a  weight 
of  corn  as  the  farmer  who  adopts  the  system  of  rotation, 
and  thus  surmises  that  his  management  has  procured 
what  the  ground  gives  of  its  own  free  will,  will  inevi- 
tably discover  that  his  fields  may  be  exhausted  of  the 
conditions  of  their  fertility,  and  that  it  is  quite  erroneous 
to  suppose  that  all  the  farmer's  art  consists  in  convert- 
ing manure  into  corn  and  flesh. 

A  simple  law  of  nature  regulates  the  permanence 
of  agricultural  produce.  If  the  amount  of  produce  is 
in  proportion  to  the  surface  presented  by  the  sum  total 
of  nutritive  substances,  in  the  soil,  the  permanence  of 
the  crops  will  depend  upon  the  maintenance  of  that  pro- 
portion. 

This  law  of  compensation,  the  replacement  of  nutri- 
tive substances  which  the  crops  have  carried  away  from 


KECOKDS   OF   CHARLEMAGNE.  233 

the  soil,  is  the  foundation  of  rational  husbandry,  and 
must,  above  all  things,  be  kept  in  view  by  the  practical 
farmer.  He  may  renounce  the  hope  of  making  his  land 
more  fruitful  than  it  is  by  nature,  but  he  cannot  expect 
to  keep  his  harvests  up  to  their  average  if  he  allows  the 
necessary  conditions  for  them  to  diminish  in  his  land. 

All  those  farmers  who  cherish  the  notion  that  the 
produce  of  their  fields  has  not  declined,  have  not  hither- 
to been  able  to  appreciate  the  force  of  this  law.  As- 
suming that  they  have  an  excess  of  nutritive  substances 
to  deal  with,  they  think  they  may  continue  drawing 
upon  it,  until  a  failure  becomes  visible,  and  then  they 
fancy  it  will  be  time  enough  to  talk  of  compensation. 

This  view  results  from  want  of  understanding  the 
nature  of  their  own  acts. 

There  surely  can  be  no  doubt  that  to  manure  a  field 
which  already  contains  an  excess  of  nutritive  substances 
is  opposed  to  a  rational  system  of  cultivation ;  for  what 
end  could  be  gained  by  increasing  the  nutritive  sub- 
stances in  a  field  where  a  portion  of  the  elements  already 
existing  cannot,  on  account  of  their  mass,  come  into 
operation  ? 

But  how  can  sensible  men  talk  of  excess  when  they 
are  obliged  to  use  manure  in  order  to  keep  up  their 
harvests,  and  when  their  crops  decline  if  they  employ 
no  manure  ? 

The  simple  fact,  say  others,  that  in  certain  districts, 
as  in  Rhenish  Bavaria,  agriculture  has  flourished  since 
the  time  of  the  Romans,  and  that  the  ground  there  is 
just  as  rich,  nay,  gives  higher  crops  than  in  other  lands, 
is  a  proof  how  little  reason  there  is  to  fear  want  or  ex- 
haustion by  continued  culture  ;  for  if  such  a  thing  were 
likely,  it  would  make  itself  manifest  there  sooner  than 
elsewhere. 

But  in  the  cultivated  lands  of  Europe  agriculture 
is  at  all  events  still  very  young,  as  we  know  with  the 
greatest  certainty  from  records  of  the  time  of  Charle- 
magne. His  ordinances  respecting  the  management 
of  his  own  estates  (capitulare  de  mills  vel  curtis  im- 
peratoris),  wherein  directions  are  given  to  the  stewards, 


234  THE   SYSTEM   OF  FAKM-YAKD    MANURING. 

as  also  the  official  reports  to  the  Emperor  (specimen 
breuiarii  reruin  fiscalium  Caroli  Magni\  sent  in  by 
inspectors  expressly  appointed  to  survey  those  estates, 
are  irrefragable  proofs  that  there  was  then  no  agricul- 
ture worth  the  name.  Very  little  is  said  in  the  ffapitu- 
lare  about  the  cultivation  of  corn,  with  the  exception 
of  millet.  It  is  reported  in  the  Breviarium,  that  at 
Stefanswerth  (a  domain  of  the  Emperor),  comprising 
740  acres  (jurnales)  of  arable  land  and  meadow,  capa- 
ble of  supplying  600  cartloads  of  hay,  the  commissioners 
found  no  corn  in  store,  but  on  the  other  hand  a  large 
number  of  cattle,  27  sickles  great  and  small,  and  only 
seven  broad  hoes,  to  till  740  acres  of  land  ! 

Upon  another  estate  were  found  80  baskets  of  last 
year's  spelt,  equivalent  to  400  Ibs.  of  flour  (=H  bushel, 
or  somewhat  more  than  3  hectolitres),  90  baskets  of 
spelt  of  the  current  year,  from  which  450  Ibs.  of  flour 
could  be  made.  On  the  other  hand,  there  were  330 
hams  ! 

The  crop  or  stock  upon  another  domain  amounted 
to  20  baskets  of  spelt  (=100  Ibs.  of  flour)  of  the  preced- 
ing year,  and  30  baskets  of  spelt,  of  which  one  was  used 
for  seed. 

It  is  easy  to  see  that  in  those  days  the  breeding  of 
cattle  was  the  chief  object,  and  that  the  cultivation  of 
corn  occupied  a  very  subordinate  position  in  husbandry.* 
A  deed  of  the  period  shortly  after  Charlemagne  says 
on  this  point :  '  Every  year,  three  yokes  of  land  upon 
an  estate  '  should  be  ploughed  and  sown  with  seed  fur- 
nished by  the  lord  of  the  manor.  (See  '  die  Getreide- 
Arten  und  das  Brod  von  Freih.  von  Bibra.'  Nurem- 
berg: Schmid.  1860.) 

Hence  we  possess  not  a  single  trustworthy  proof  that 
any  one  field  in  Germany  or  France  (perhaps  we  may 
make  an  exception  in  favour  of  Italy)  has  served  for 
the  cultivation  of  corn  from  the  time  of  Charlemagne 
to  our  own  age ;  and  the  argument  for  the  inexhausti- 

*  It  is  worthy  of  remark  that  Charlemagne  introduced,  upon  his 
estates,  the  three-field  system,  with  which  he  had  become  acquainted  in 
Italy. 


EXHAUSTION   OF  RHENISH   BAVARIA.  235 

bility  of  land  is  almost  childish,  because  it  assumes  that 
corn  may  be  continuously  taken  from  a  field,  without 
restoring  the  conditions  of  reproduction.  A  field  does 
not  necessarily  become  unfruitful  for  corn  because  it 
has  yielded  large  corn-crops ;  but  it  ceases  to  yield  corn- 
crops  if  it  does  not  receive  compensation  for  the  corn- 
constituents  which  have  been  removed.  This  compen- 
sation is  facilitated  by  the  breeding  of  cattle,  in  propor- 
tion to  the  extent  to  which  this  is  carried,  and  especially 
when  the  cultivator  is  acquainted  with  the  operation 
of  manure.  In  the  time  of  Charlemagne  this  was  well 
known,  for  the  winter-crops  were  manured  with  dungr 
distinguished  as  cattle-dung  (called  gor)  and  horse-dung 
(dost  or  deist).  Besides,  the  practice  of  marling  was 
then  common  in  Germany. 

"With  regard  to  the  special  instance  of  Rhenish 
Bavaria  as  proving  the  inexhaustibility  of  the  soil,  I 
had  an  opportunity  last  autumn,  at  a  meeting  of  the 
Society  of  Naturalists  at  Spires,  of  making  particular 
inquiries  about  the  actual  condition  of  the  neighbour- 
hood. Rhenish  Bavaria,  from  the  slopes  of  the  Hardt 
mountains  to  the  Rhine,  comprises  a  district  of  great 
fertility :  the  region  is  inhabited  by  an  extremely  in- 
dustrious population,  distributed  in  small  towns  and 
villages.  Almost  every  artisan,  even  to  the  tailor  and 
shoemaker,  possesses  a  small  plot  of  ground,  on  which 
he  raises  his  potatoes  and  vegetables.  The  export  of 
corn  from  this  district  is  never  thought  of,  but  on  the 
contrary  corn  and  a  large  quantity  of  manure  are  im- 
ported from  Mannheim,  Heidelberg,  and  elsewhere.  The 
manuring  substances  obtained  from  the  houses  of  the 
towns  and  villages  are  carefully  treasured  and  employed, 
so  that  there  can  be  no  fear  of  exhaustion,  since  the 
removed  nutritive  substances  are  restored  to  the  fields. 
In  spite  of  all  this,  in  no  part  of  Germany  is  the  want 
of  manure  more  felt  than  there.  On  the  highways  chil- 
dren are  constantly  seen  with  little  baskets,  following 
the  horses  and  swine,  to  gather  the  manure  dropped  by 
those  animals.  In  the  year  1849,  during  the  political 
agitation  in  the  Palatinate,  the  peasants  had  no  more 


236  THE   SYSTEM   OF   FARM-YARD   MANURING. 

urgent  request  for  the  improvement  of  their  condition 
to  lay  before  the  magistrates,  than  a  petition  to  be  al- 
lowed to  collect  <  forestings,'  that  is,  to  carry  off  the 
natural  manure  from  the  forests  for  the  benefit  of  their 
fields.  They  urged  that  without  this  (very  pitiful)  ad- 
dition to  their  manure,  the  future  prospects  of  agricul- 
ture in  the  Palatinate  were  endangered.  In  fact,  a 
great  quantity  of  manure  is  laid  out  upon  the  vineyards 
and  tobacco  fields,  which  give  none  in  return ;  hence 
the  increasing  want. 

There  can  be  no  doubt  that  in  the  earliest  periods 
most  of  our  cultivated  fields  gave  a  succession  of  abun- 
dant crops,  without  manuring,  as  in  the  case  even  now, 
with  many  fields  in  the  United  States  of  America.  But 
no  fact  has  ever  yet  been  more  clearly  established  by 
experience  than  this,  that  in  the  course  of  a  few  genera- 
tions all  such  fields  are  found  perfectly  unsuited  for  the 
growth  of  wheat,  tobacco,  and  cotton,  and  that  they  re- 
cover their  fertility  only  by  manuring. 

I  know  full  well  that  recorded  facts  have  as  little 
weight  with  ignorant  c practical  men'  as  those  of  politi- 
cal history  with  practical  statesmen,  who  also  act  ac- 
cording to  '  circumstances  and  contingencies,'  and  are 
simply  led  when  they  fondly  believe  they  lead.  Still, 
the  reflecting  mind  cannot  fail  to  be  struck  by  the  cir- 
cumstance, that  it  is  just  in  countries  where  the  land  is 
most  positively  known  to  have  given  for  above  4000 
years,  without  manuring  by  the  hand  of  man,  an  unin- 
terrupted succession  of  abundant  crops,  that  the  full 
action  of  the  great  law  of  restitution  is  most  clearly, 
seen. 

We  know,  most  positively,  that  the  corn-fields  in 
the  valley  of  the  Nile  and  the  basin  of  the  Ganges  re- 
main permanently  fruitful,  simply  because  nature  has 
taken  upon  herself  to  restore  the  lost  condition  of  pro- 
ductiveness to  the  soil  in  the  mud  deposited  by  the 
inundation  of  these,  rivers  which  gradually  raises  the 
land. 

All  the  fields  that  are  not  reached  by  the  river  lose 
their  productiveness  unless  manured.  In  Egypt,  the 


THE    SOIL   NOT   INEXHAUSTIBLE.  237 

amount  of  the  crop  to  be  expected  is  calculated  from 
the  height  of  the  water  of  the  Nile ;  and  in  the  East 
Indies  a  famine  is  the  inevitable  consequence  whenever 
there  happens  to  be  no  inundation. 

Nature  herself,  in  these  striking  instances,  points 
out  to  man  the  proper  course  of  proceeding  for  keeping 
up  the  productiveness  of  the  land.  (See  Appendix  H.) 

The  notion  of  our  ignorant  practical  husbandmen, 
that  the  soil  contains  ample  store  of  the  elements  of  food 
to  enable  them  to  pursue  their  system  of  agriculture,  is 
due  partly  to  the  excellent  quality  of  the  land,  but  also 
to  their  skill  in  robbing  it.  The  man  who  attempts  to 
gain  money  by  filing  the  weight  of  one  gold  piece  from 
a  thousand,  cannot  plead,  in  extenuation,  that  it  is  re- 
marked by  no  one,  but  if  discovered  he  is  punished  by 
the  law  ;  for  everybody  knows  that  the  fraudulent  act, 
repeated  a  thousand  times,  would  ultimately  leave 
nothing  of  the  gold  pieces.  A  similar  law,  from  which, 
moreover,  there  is  no  escape,  punishes  the  agriculturist 
who  would  make  us  believe  that  he  knows  the  exact 
store  of  available  food  elements  in  his  land,  and  how  far 
it  will  go ;  and  who  deceives  himself  when  he  fancies 
he  is  enriching  his  field  by  bestowing  on  the  arable  sur- 
face soil  the  matters  taken  from  the  deeper  layers. 

There  is  another  class  of  agriciilturists  consisting  of 
men  with  a  small  stock  of  knowledge  joined  to  a  limited 
understanding,  who,  indeed,  fully  recognise  the  law  of 
restitution,  but  interpret  it  after  their  own  fashion. 
They  assert  and  teach  that  part  of  the  law  only,  and 
not  the  whole,  applies  to  cultivated  fields  ;  that  certain 
constituents,  unquestionably,  must  be  restored  to  the 
soil  to  keep  up  its  productiveness,  but  that  all  the  others 
are  found  in  the  earth  in  inexhaustible  quantities.  They 
generally  base  their  opinion  upon  some  unmeaning 
chemical  analysis,  and  demonstrate  to  the  simple  agri- 
culturist (for  whom  alone  such  disquisitions  are  intend- 
ed) how  rich  his  fields  still  are  in  some  one  or  other  of 
the  mineral  constituents,  and  for  how  many  hundred 
thousand  crops  the  store  will  still  suffice  ;  as  if  it  could 
be  of  the  least  use  for  any  one  to  know  what  the  soil 


238  THE   SYSTEM   OF   FARM-YARD   MANURING. 

contains,  if  the  amount  of  the  available  food  elements 
that  serve  to  produce  the  crops,  which  is  the  really  im- 
portant point,  cannot  be  determined. 

With  such  absurd  assertions  they  absolutely  hood- 
wink our  '  practical '  farmers,  who,  but  for  them,  might 
see  clearly  into  matters,  but  who  appear  only  too  will- 
ing to  accept  any  assertion  that  will  only  leave  them  at 
peace,  and  save  them  the  trouble  of  c  thinking.' 

I  remember  a  case  wThere  a  swindler  offered  to  sell 
to  a  wealthy  gentleman,  at  a  high  price,  a  mine  of 
almost  pure  oxide  of  aluminium,  after  having  shown 
him,  from  chemical  works,  that  oxide  of  aluminium  was 
indispensable  for  the  production  of  the  metal  alumin- 
ium, the  market  price  of  which  was  as  much  as  41.  per 
pound,  and  that  the  ore  of  the  mine  offered  for  sale  con- 
tained nearly  80  per  cent,  of  that  valuable  metal.  The 
purchaser  was  not  aware  that  the  ore  in  question  is  gen- 
erally known  as  '  pipe-clay,'  an  article  of  almost  nom- 
inal value,  and  that  the  high  price  of  the  metal  arises 
from  the  many  changes  through  which  the  oxide  has  to 
pass  to  effect  its  reduction  to  the  metallic  state. 

It  is  generally  the  same  with  the  great  stores  of  pot- 
ash in  the  soil.  The  alkali  in  the  ground,  to  answer 
the  intended  purpose,  must,  by  the  agriculturist's  art, 
be  converted  first  into  a  certain  form,  in  which,  alone, 
it  is  available  as  food  for  plants ;  and  if  he  does  not 
understand  how  to  effect  this  conversion,  all  the  potash 
in  his  soil  is  of  no  earthly  use  to  him. 

The  notion  that  the  farmer  need  only  restore  to  his 
land  certain  substances,  without  troubling  himself  about 
the  rest,  might  not  be  prejudicial  if  those  who  enter- 
tained it  confined  the  application  to  their  own  farms ; 
but,  as  a  matter  of  instruction  to  others,  it  is  untrue 
and  quite  exceptionable.  It  is  calculated  for  the  low 
intellectual  standard  of  the  practical  man,  who,  if  he  in 
any  way  succeeds,  by  certain  alterations,  in  his  system, 
or  by  the  use  of  certain  manuring  agents  in  obtaining 
better  results  than  another,  attributes  his  success  to  his 
own  sagacity  rather  than  to  the  superior  quality  of  his 
land.  He  does  not  even  know  that  the  other  has  tried 


IGNORANT   PRACTICAL    MEN.  239 

the  very  same  plans  as  himself,  only  without  attaining  so 
favourable  a  result.  Our  ignorant  practical  husband- 
man starts  upon  the  assumption  that  all  fields  are  the 
same  in  condition  as  his  own,  and  that,  therefore,  the 
same  system  which  answers  on  his  farm  ought  to  do 
equally  well  on  every  other ;  that  the  manure  which  he 
finds  useful  ought  to  be  equally  useful  to  others ;  that 
the  deficiencies  in  his  field  are  the  same  in  all  other 
fields ;  that  what  he  exports  from  his  land,  others  ex- 
port from  theirs  ;  and  what  he  is  called  upon  to  restore 
to  his  soil,  others  are  equally  called  upon  to  restore  to 
theirs. 

Although  he  knows  next  to  nothing  of  the  condition 
of  his  own  land,  with  which  it  would,  indeed,  require 
many  years  of  careful  observation  to  become  familiar, 
and  is  most  profoundly  ignorant  about  the  condition  of 
the  land  in  any  other  part ;  although  he  never  has  troub- 
led himself  with  reflecting  upon  the  causes  of  his  suc- 
cess in  the  cultivation  of  his  fields,  and  is  quite  aware 
that  the  advice  of  agriculturists  from  other  parts, 
respecting  manuring,  rotation  of  crops,  and  the  general 
treatment  of  his  own  land,  is  not  of  the  slightest  use  to 
him,  because,  as  he  has  found,  if  is  not  at  all  applicable 
to  his  district ;  yet  all  this  does  not  prevent  him  from 
wanting  to  instruct  others,  and  persuade  them  that  his 
system  is  the  only  true  one,  and  that  they  need  only  do 
as  he  does  to  obtain  equally  favourable  results. 

The  foundation  of  all  such  views  is  a  total  miscon- 
ception of  the  nature  of  the  soil,  the  condition  and  com- 
position of  which  present  an  infinite  variety  of  shades. 

The  fact  that  many  fields  that  happen  to  be  rich  in 
silicates,  and  in  lime,  potash,  and  magnesia,  are,  by  the 
growth  of  corn  upon  the  common  farm-yard  manuring 
system,  drained  only  of  phosphoric  acid  and  nitrogen, 
and  that  the  farmer  need  only  look  to  the  replacement 
of  these  matters  without  troubling  his  mind  about  the 
rest,  has  already  been  fully  discussed.  This  fact  no  one 
can  dispute :  but  it  is  utterly  inadmissible  to  apply  it 
to  the  case  of  other  fields,  and  to  make  other  farmers  be- 
lieve that  they,  too,  need  not  trouble  their  minds  about 


24:0  THE    SYSTEM    OF    FARM- YARD    MANURING. 

supplying  to  their  land  potash,  lime,  magnesia,  or  silicic 
acid,  and  that  salts  of  ammonia  and  superphosphate  of 
lime  will  suffice  to  restore  the  productiveness  of  all 
exhausted  fields. 

A  farmer  may,  therefore,  be  quite  justified  in  con- 
sidering that  his  field  can  never  grow  poorer  in  potash 
because  he  never  takes  any  from  it,  or  that  it  actually 
contains  a  superabundance  of  potash  since  every  rota- 
tion tends  to  accumulate  in  the  soil  a  fresh  amount  of 
that  ingredient ;  but  it  is  childish  of  him  to  think  him- 
self justified  by  this  circumstance  in  assuring  another 
agriculturist,  about  whose  system  of  cultivation  he 
knows  nothing,  that  the  fields  of  the  latter  equally  con- 
tain a  superabundance  of  potash. 

There  are  millions  of  acres  of  fertile  land  (sand  and 
clay-soil),  in  which  the  proportion  of  lime  or  magnesia 
in  the  soil  does  not  exceed  that  of  phosphoric  acid,  and 
where  provision  must  be  made  for  replacing  the  former 
as  well  as  the  latter.  Again,  there  are  millions  of  acres 
of  fertile  land,  which,  like  calcareous  soils  in  general, 
are  exceedingly  poor  in  potash,  and  become  absolutely 
barren  without  a  proper  supply  of  this  ingredient. 

There  are,  on  the  other  hand,  millions  of  acres  of 
fertile  fields  abounding  so  richly  in  nitrogen  that  any 
additional  supply  of  that  element  would  be  mere  waste. 

Ashes  will  not  promote  the  growth  of  clover  on  fields 
abounding  in  potash,  whilst  the  application  of  manur- 
ing agents  containing  phosphoric  acid  will  have  that 
effect ;  on  the  other  hand,  ashes  will  make  clover  grow 
on  land  deficient  in  potash,  where  bone-earth  proves 
useless ;  and  a  simple  supply  of  lime  containing  mag- 
nesia will  often  suffice  to  restore  the  productiveness  for 
clover  where  the  land  is  deficient  in  lime  and  mag- 
nesia. 

When  a  farmer,  besides  corn  and  flesh,  grows  and 
sells  other  produce,  the  nature  of  the  required  supply 
of  mineral  elements  is  thereby  necessarily  altered.  In 
the  average  potato  produce  of  three  hectares  of  land 
we  take  away  the  seed-constituents  of  four  wheat  crops, 
besides  about  600  Ibs.  of  potash,  and  in  the  average 


MATTERS    TO    BE    RESTORED    VARY.  241 

turnip  produce  of  three  hectares  the  seed-constituents 
of  four  wheat-crops,  besides  about  1000  Ibs.  of  potash. 
A  supply  of  phosphoric  acid  alone  will  not  suffice,  in 
this  case,  to  keep  up  the  productiveness  of  the  land. 

The  grower,  of  commercial  plants,  such  as  tobacco, 
hemp,  flax,  the  vine,  &c.,  must  in  like  manner  strictly 
attend  to  the  law  of  restitution,  which,  properly  inter- 
preted, does  not  imply  that  he  should  bestow  tne  same 
anxious  care  upon  the  replacement  of  all  constituents 
alike  which  have  been  taken  away  in  the  crops.  It 
would,  for  instance,  be  the  height  of  absurdity  to  re- 
quire the  tobacco  planter  who  grows  his  crops  on  a  lime 
or  marl  soil,  to  replace  the  lime  carried  off  in  the  leaves 
of  the  plant.  But  it  tells  him  that  not  all  that  goes  by 
the  name  of  manure  is  useful  for  his  fields,  and  it  shows 
him  the  difference  between  manures  :  it  informs  him  of 
the  loss  inflicted  upon  the  soil  by  the  preceding  crop, 
and  the  supply  required  to  insure  future  harvests ;  it 
teaches  him  never  to  allow  himself  to  be  guided  in  his 
proceedings  by  the  opinions  of  persons  who  do  not  take 
the  slightest  interest  in  him  and  his  land,  but  always  to 
act  upon  his  own  observations.  A  careful  study  of  the 
weeds  that  spring  up  spontaneously  in  his  fields  may 
frequently  prove  more  useful  in  this  respect  than  a  heap 
of  hand-books  on  agriculture. 

If  after  the  foregoing  statements  the  condition  of 
the  cultivated  land  in  Europe,  and  the  decline  towards 
which  agriculture  is  tending  by  the  prevailing  system 
of  farm-yard  manuring,  should  still  be  a  matter  of 
doubt  to  many  persons  unacquainted  with  the  natural 
sciences,  and  who  trust  only  to  definite  numbers  as 
palpable  facts,  that  doubt  may,  perhaps,  be  removed 
by  statistical  data  on  the  corn  produce  of  the  land  in 
different  parts  of  Germany,  which  have  been  collected 
partly  by  order  of  the  government. 

For  a  correct  appreciation  of  the  importance  of 
these  data  in  the  matter,  it  is  necessary  in  the  first 
place  to  understand  clearly  what  is  meant  by  an 
'  average '  crop.  By  this  term  is  designated  the  aver- 
age produce,  expressed  in  numbers,  of  a  field,  or  a 
11 


24:2  THE   SYSTEM   OF   FARM-YAKD   MANURING. 

number  of  fields,  or  all  the  fields  of  a  district  or  coun- 
try. The  figure  which  represents  it  is  found  by  adding 
together  the  produce  of  all  the  fields  for  a  number  of 
years,  and  dividing  the  sum  total  by  the  latter.  There 
is  accordingly  a  special  average  produce  for  every  dis- 
trict, by  which  tne  next  year's  crop  is  judged.  Thus 
we  talk  of  a  full,  or  a  half,  or  a  three-quarter  average, 
as  the  produce  happens  to  come  up  to  the  calculated 
average,  or  fall  one-half  or  one  quarter  below  it. 

The  question  as  to  the  actual  condition  of  our  corn- 
fields may  therefore  be  put  thus  :  Has  there  been  any 
change  in  the  figure  which  at  any  previous  period  ex- 
pressed the  average  produce  of  the  land,  and  in  wThat 
sense  ?  Is  that  figure  higher  now  than  formerly,  or  has 
it  remained  the  same  or  fallen  ?  If  the  figure  is  higher, 
this  is  of  course  a  sign  of  an  improved  condition  of  the 
land ;  if  it  remains  the  same,  the  condition  has  under- 
gone no  change ;  and  if  it  is  lower,  there  can  be  no 
doubt  that  the  condition  of  the  land  in  that  district  has 
declined. 

I  select  for  my  purpose  the  statistical  data  of  the 
produce  of  the  Hessian  Rhine  district,  one  of  the  most 
fertile  provinces  of  the  Grand  Duchy  of  Hesse,  with  an 
excellent  wheat  soil,  and  inhabited  by  a  most  indus- 
trious and  generally  well  educated  population.  ('  Sta- 
tistische  Mittheilungen  iiber  Kheinhessen,  von  F.  Dael, 
DLL.'  Mayence :  1849.  Flor.  Kupferberg.) 

These  data  embrace  a  period  of  fifteen  years,  from 
1833  to  1847  ;  they  refer  accordingly  to  the  time  when 
guano  was  not  yet  used  as  manure  in  Germany.  The 
use  of  bone-earth  wTas  at  that  time  also  still  very  limit- 
ed, and  hardly  worth  taking  into  account. 

A  produce  of  eleven  grains  of  wheat  to  every  two 
grains  sown,  of  five  and  a  half  accordingly,  was  held  to 
be  an  average  crop  for  the  Hessian  Rhine  district.  (20 
makers  —  14  bushels  =  5120  hectolitres  per  hectare  = 
2-471  English  acres.) 

Taking  the  figure  1  to  express  an  average  crop,  the 
amount  of  produce  reaped  in  the  Rhine  district  of 
Hesse  was :— 


MEAN   OF   AVERAGE   CROPS   IN   RHINE   HESSE.         243 

1833.       1834.       1835.       1836.       1837.       1838.       1839. 

0-85    0-78    0-88    0'72    0'88    0'73    0'61 

1840.      1841.       1842.      1843.       1844.      1845.       1846.       184T. 

1-10         0-40         0-PO         0-74         1-02         0'G3         0'75         O'SS 

which  gives  a  mean  for  the  fifteen  years  of  0*79  of  the 
former  average. 

The  productiveness  of  the  wheat  land  in  the  Rhine 
district  of  Hesse  has  therefore  declined  somewhat  more 
than  one-fifth. 

I  know  all  that  may  be  urged  against  the  accuracy 
of  these  figures  severally,  and  their  trustworthiness  col- 
lectively ;  but  if  they  contain  errors,  the  impartial 
observer  must  see  that  these  must  tend  to  the  plus  as 
well  as  to  the  minus  side,  and  that  it  would  be  most 
extraordinary  in  the  presence  of  plus  errors  that  all  the 
estimates  should  have  falleij  out  on  the  minus  side. 

There  is,  however,  a  very  simple,  and  at  the  same 
time  infallible  and  irrefutable,  proof  of  the  correctness 
of  the  conclusions  drawn  from  these  figures,  in  the  fact 
that  the  cultivation  of  wheat  is  on  the  decrease,  that  of 
rye  on  the  increase,  in  Khine  Hesse,  and  that  many 
fields  on  which  wheat  was  formerly  grown  are  now 
turned  into  rye  fields. 

Properly  understood,  the  change  from  wheat  to  rye 
always  argues  a  deterioration  in  the  quality  of  the  soil ; 
the  farmer  begins  to  grow  rye  in  a  wheat  field  only 
when  the  latter  no  longer  gives  remunerative  wheat 
crops. 

In  Rhine  Hesse,  a  4j-  fold  produce  of  rye  is  consid- 
ered an  average  crop  ;  a  wheat  soil,  therefore,  capable 
of  giving  only  four-fifths  of  an  average  wheat-crop,  can 
produce  a  full  average  rye-crop. 

Now  the  average  produce  of  rye  in  the  fifteen  years 
is  0-96,  which  pretty  nearly  corresponds  with  the  full 
average. 

For  spelt,  the  mean  was  0*79  of  the  average ;  for 
barley,  0'88  ;  for  oats,  0*88  ;  for  peas,  0'67 ;  for  pota- 
toes, on  the  other  hand,  0*98  ;  and  for  colewort  and 
turnips,  0'85. 

The  statistical  data  collected  in  Prussia  and  Bava- 


244  THE   SYSTEM   OF   FARM-YARD   MANURING. 

ria,  which  are  most  reliable,  give  the  same  result ;  and 
I  have  not  the  slightest  doubt  that  it  would  hold  equally 
true  with  France  arid  other  countries,  England  includ- 
ed. The  visible  gradual  deterioration  of  the  arable  soil 
cannot  but  command  the  serious  attention  of  all  men 
who  take  an  interest  in  the  public  welfare.  It  is  of  the 
utmost  importance  that  we  do  not  deceive  ourselves  re- 
specting the  danger,  indicated  by  these  signs,  as  threat- 
ening the  future  of  the  populations.  An  impending 
evil  is  not  evaded  by  denying  its  existence  or  shutting 
our  eyes  to  the  signs  of  its  approach.  It  is  our  duty  to 
examine  and  appreciate  the  signs  :  if  the  source  of  the 
evil  is  once  detected,  the  first  step  is  thereby  taken  to 
remove  it  for  ever. 


CHAPTER   VI. 

GUANO. 

Composition  compared  with  that  of  seeds  ;  small  amount  of  potash  in  it ;  its  ac- 
tion— Guano  and  bone-earth,  similarity  of  their  active  ingredients — Guano 
acts  quicker  than  bone-earth,  or  a  mixture  of  the  latter  and  ammoniacal  salts  ; 
reason  of  this — Oxalic  acid  in  Peruvian  guano  ;  the  phosphoric  acid  rendered 
soluble  by  its  means— Peruvian  guano,  its  efl'ect  on  the  cultivation  of  corn- 
Moist  guano  loses  ammonia — Moistening  guano  with  water  acidulated  with 
sulphuric  acid ;  effect — Inactivity  of  guano  in  dry  and  very  wet  weather — 
Rapidity  of  its  action  as  a  manure,  on  what  dependent— Comparison  of  the 
effect  of  farm-yard  manure  and  guano  ;  effect  produced  by  mixing  the  two — 
Guano  on  a  field  rich  in  ammonia— Increased  produce  by  guano,  what  it  pre- 
supposes— Exhaustion  of  the  soil  by  continuous  use  of  guano — Mixture  of 
guano  with  gypsum  and  with  sulphuric  acid — The  Saxon  agricultural  experi- 
ments ;  their  results. 

PERUVIAN  guano  generally  contains  33  to  34  per 
cent,  of  incombustible,  and  66  to  67  per  cent,  of 
volatile  and  combustible  ingredients  (water  and  ammo- 
nia). The  latter  consist  principally  of  uric  acid,  oxalic 
acid,  a  brown  matter  of  uncertain  composition,  and 
guanine.  The  uric  acid  amounts  occasionally  to  as 
much  as  18  per  cent.,  the  oxalic  acid  generally  to  8  or 
10  per  cent,  of  the  weight  of  the  guano.  The  relation 
of  uric  acid  to  vegetation  is  not  known,  but  it  is  hardly 
likely  that  this  substance  can  have  a  perceptible  share 
in  the  fertilising  action  of  guano.  To  account  for  this 
action,  then,  we  have  only  the  ammonia  and  the  incom- 
bustible constituents  left  to  consider.  An  analysis  of 
two  samples  of  guano,  made  by  Dr.  Mayer  and  Dr. 
Zoeller,  in  iny  own  laboratory,  showed  100  parts  of 
guano  ash  to  contain  : — 

Potash 1-56  to  2'03 

Lime 34'00  "  37 '00 

Magnesia 2-56   "  2'00 

Phosphoric  acid 41 '00  "  40'00 


216  GUANO. 

If  we  compare  with  this  the  composition  of  the  ashes 
of  various  seeds,  we  see  at  once  that  the  incombustible 
constituents  of  guano  do  not  altogether  replace  the  soil 
constituents  carried  off  in  the  seeds. 

In  100  parts  of  seed  ash  are  contained, — 

Wheat.  Peas  and  beans.  Rape. 

Potash 30  40  24 

Lime 4  6  10 

Magnesia 12  6  10 

Phosphoric  acid 45  36  36 

The  principal  difference  between  the  ash  of  guano 
and  that  of  these  seeds  lies  in  the  deficiency  of  potash 
and  magnesia  in  the  former. 

Agriculturists  are  generally  agreed  about  the  neces- 
sity of  potash  for  vegetation,  and  that  a  supply  is  re- 
quired by  fields  poor  in  that  ingredient,  or  drained  of 
it ;  but  the  question  as  to  the  importance  of  magnesia 
for  seed  formation  has  not,  as  yet,  met  with  the  same 
attention,  and  special  experiments  in  this  direction 
would  be  very  desirable.  The  fact  that  much  more 
magnesia  is  found  in  the  seeds  than  in  the  straw  unmis- 
takably shows  that  it  must  play  a  definite  part  in  the 
formation  of  the  seed,  which  might,  perhaps,  be  ascer- 
tained by  a  careful  examination  of  seeds  of  the  same 
variety  of  plants  containing  different  amounts  of  mag- 
nesia. It  is  a  well-known  fact  that  the  seeds  of  the 
several  species  of  cereals  having  the  same  proportion  of 
nitrogen,  do  not  always  contain  the  same  nitrogenous 
compounds,  and  it  is  possible  that  the  nature  of  the  lat- 
ter may,  in  the  formation  of  the  seeds,  be  essentially  in- 
fluenced by  the  presence  of  lime  or  of  magnesia,  so  that 
the  differences  in  the  proportions  of  both  of  these  alka- 
line earths  may  have  a  certain  connection  with  the  pres- 
ence of  the  soluble  nitrogenous  compounds  (albumen 
and  casein),  or  of  the  insoluble  (gluten  or  vegetable 
fibrine).  Of  course,  the  quantity  of  potash  and  soda 
present  would  have  to  be  taken  into  account  in  an  in- 
vestigation of  the  kind.  The  fertilising  action  of  guano 
is  generally  attributed  to  the  ammonia  in  it,  and  to  the 
other  ingredients  rich  in  nitrogen  ;  but  accurate  experi- 


OXALATE   OF  AMMONIA   IN   GUANO.  247 

ments  made  to  elucidate  this  point,  by  the  General 
Committee  of  the  Agricultural  Society  of  Bavaria, 
which  we  shall  hereafter  have  occasion  to  mention, 
have  shown  that  whilst  the  use  of  guano  was  found,  in 
many  cases,  to  increase  very  considerably  the  produce 
of  corn  and  straw  of  a  field,  the  application  of  an  am- 
moniacal  salt  containing  an  amount  of  nitrogen  cor- 
responding to  that  in  the  guano  produced  no  perceptible 
effect  on  the  crop  of  the  same  cereal,  grown  in  the 
same  year,  upon  another  plot  of  the  field,  when  com- 
pared with  the  produce  of  a  third  unmanured  plot  of 
the  same  field. 

Though  the  part  which  the  ammonia  in  the  guano 
plays,  in  many  cases,  in  increasing  the  produce,  cannot 
be  questioned  ;  yet  it  is  equally  certain,  on  the  other 
hand,  that  in  many  other  instances  the  fertilising  action 
of  guano  must  be  attributed  principally  to  its  other  con- 
stituents. 

If  the  ash  of  guano  is  compared  with  calcined  bones, 
or  bone-earth,  it  is  found  that  the  difference  between 
the  two  is  not  very  great ;  yet  an  amount  of  bone-earth 
containing  the  same  proportion  of  earthy  phosphate  as 
in  guano,  or  even  two  to  four  times  that  quantity,  has 
not  the  same  action  as  the  latter  manure.  Even  a  mix- 
ture of  bone-earth  with  ammoniacal  salts  in  sufficient 
proportion  to  make  the  amount  of  nitrogen  and  phos- 
phoric acid  equal  to  that  contained  in  the  guano,  though 
more  efficacious  than  bone-earth  alone,  has  still  a  dif- 
ferent action  from  guano.  The  great  distinction  be- 
tween the  two  lies  in  the  greater  rapidity  of  the  action 
of  the  guano  in  the  first  year,  and  often  even  in  the 
course  of  a  few  weeks,  whilst  in  the  year  after  it  is 
barely  perceptible  ;  that  of  the  bone-earth,  on  the  other 
hand,  is  comparatively  slight  in  the  first  year,  but  in- 
creases in  the  following. 

The  cause  of  this  difference  of  action  is  the  oxalic 
acid  in  Peruvian  guano,  which  often  amounts  to  from  6 
to  10  per  cent.  If  guano  is  subjected  to  lixiviation,  the 
water  dissolves  sulphate,  phosphate,  and  oxalate  of  am- 
monia, which  latter  salt  crystallises  out  abundantly 


248 


GUANO. 


upon  evaporating  the  solution.  But  if  the  guano  is 
moistened  with  water,  without  lixiviating,  and  is  then 
left  to  itself,  it  is  found,  upon  extracting  with  water 
portions  of  the  mixture  from  time  to  time,  that  the  pro- 
portion of  the  oxalic  acid  in  the  solution  gradually  de- 
creases, wrhilst  that  of  the  phosphoric  acid  increases.  A 
decomposition  takes  place  in  this  moistened  condition 
of  the  guano,  through  the  agency  of  the  sulphate  of  am- 
monia, by  which  the  phosphate  of  lime  is  converted  into 
oxalate  of  lime  and  phosphate  of  ammonia.  Peruvian 
guano  is,  in  this  respect,  a  very  remarkable  mixture, 
which  could  scarcely  have  been  more  ingeniously  com- 
pounded for  the  purposes  of  the  nutrition  of  plants  ;  for 
the  phosphoric  acid  in  it  becomes  soluble  only  in  a 
moist  soil,  through  which  it  then  spreads  in  form  of 
phosphate  of  potash,  phosphate  of  soda,  and  phosphate 
of  ammonia. 

The  action  of  guano  may  rather  be  compared  to  a 
mixture  of  superphosphate  of  lime,  ammonia,  and  salts 
of  potash,  which,  indeed,  in  many  cases,  is  equal  to  it. 
On  a  soil  abounding  in  lime,  guano  is,  however,  decid- 
edly more  advantageous  than  superphosphate  of  lime, 
since  the  latter,  upon  coming  in  contact  with  the  car- 
bonate of  lime  in  the  soil,  is  at  once  converted  into  neu- 
tral phosphate  of  lime,  which  requires  to  meet  with 
another  solvent  at  the  place  of  formation  to  effect  its 
diifusion  through  the  soil,  whilst  phosphate  of  ammonia 
spreads  through  a  lime  soil  just  as  if  there  wTas  no  car- 
bonate of  lime  in  it.  The  phosphate  of  ammonia  formed 
when  guano  is  moistened  with  water  (PO5  +  3NH4O), 
loses  in  the  air  one-third  of  the  ammonia.  It  is  owing 
to  this  circumstance  that  guano,  when  quite  dry,  will 
keep  without  alteration ;  whereas,  when  it  has  been 
fraudulently  moistened,  to  increase  the  wreight,  it  loses, 
by  keeping,  considerably  in  ammonia. 

If  guano,  just  before  its  application  on  the  field,  is 
moistened  with  water  and  a  little  sulphuric  acid,  suf- 
ficient to  give  the  water  a  slightly  acid  reaction,  the 
decomposition  now  mentioned,  which  otherwise  requires 
days  and  weeks,  is  effected  in  a  few  hours. 


ADDITION   OF  GUANO  TO  FAKM-YAKD  MANURE. 

That  guano  should  not  produce  much  effect  in  very 
dry  weather  needs  no  explanation,  because,  without 
water,  no  substance  will  act  in  the  ground ;  that  it 
should,  however,  equally  fail  in  very  wet  weather,  is, 
undoubtedly,  owing  in  part  to  the  fact  that  the  oxalic 
acid  is  washed  out,  as  an  ammoniacal  salt,  by  the  rain 
water,  and  that  there  is,  accordingly,  a  corresponding 
quantity  of  phosphoric  acid  not  made  soluble.  By  the 
above  simple  and  cheap  means  the  injurious  influence 
of  wet  weather  upon  guano  may  be  completely  guarded 
against,  inasmuch  as  the  water  and  sulphuric  acid  en- 
sure the  conversion  into  a  soluble  form  of  the  whole  of 
the  phosphoric  acid,  which  could  have  been  brought  in 
to  that  condition  by  the  oxalic  acid. 

The  rapidity  with  which  a  nutritive  substance  em- 
ployed in  the  shape  of  manure  produces  an  effect,  de- 
pends essentially  upon  the  speed  with  which  it  spreads 
through  the  soil,  and  this,  again,  upon  its  solubility ; 
hence  it  is  easy  to  understand  why  guano  surpasses,  in 
these  respects,  many  other  manures. 

As  regards  certainty  of  action,  guano  will  not  bear 
comparison  with  farm-yard  manure,  which,  from  its 
nature,  is  effective  in  all  cases ;  for  farm-yard  manure 
restores  to  the  land  all  the  soil  constituents  of  the  pre- 
ceding rotations,  though  not  in  the  same  proportions, 
whereas  guano  restores  only  some  of  them,  and  cannot, 
therefore,  replace  farm-yard  manure.  As  guano,  how- 
ever, contains,  with  the  exception  of  a  certain  quantity 
of  potash,  the  chief  constituents  (phosphoric  acid  and 
ammonia). of  the  exported  corn  and  flesh,  the  addition 
of  a  certain  proportion  of  guano  to  farm-yard  manure 
may  serve  to  restore  the  proper  composition  of  the  lat- 
ter, and,  with  it,  also  that  of  the  soil. 

Let  us  suppose,  for  the  purpose  of  illustration,  that 
a  hectare  of  land  has  been  manured  with  800  cwt.  of 
farm-yard  manure,  containing,  according  to  Voelker's 
analysis,  272  kilogrammes  of  phosphate,  and  that  the 
field  has,  at  the  end  of  the  rotation,  returned  the  same 
quantity  of  farm-yard  manure  of  the  same  composition, 
and  has  lost  by  the  corn  and  the  animal  produce  export- 
11* 


250  GUANO. 

ed,  altogether  135  kilogrammes  of  phosphates  ;  the  pro- 
ductive power  of  this  field,  in  so  far  as  it  depends  upon 
the  phosphates,  would  not  only  remain  unaltered,  but 
would  even  be  considerably  increased,  by  adding  to  the 
800  cwt.  of  farm-yard  manure  supplied  to  it  at  the  com- 
mencement of  a  fresh  rotation,  400  Ibs.  of  guano  (with 
34  per  cent,  of  phosphates  in  it). 

Kilogrammes. 

The  farm-yard  manure  supplied  to  the  land  .  .272  of  phosphates. 
In  the  produce  exported  the  field  lost  .  .  .135  u 

There  remained  in  the  arable  soil      ....       137  " 

In  the  new  rotation  was  added  by  the  fresh  supply  of 

800  cwt.  of  farm -yard  manure  .         .         .272 

By  the  addition  of  the  400  Ibs.  of  guano  .        .         .135 

Altogether     .        . '       .         .        .        .        .       544  " 

At  the  beginning  of  the  new  rotation  the  arable  soil 
contained,  accordingly,  twice  as  much  phosphates  as  at 
the  beginning  of  the  preceding  one. 

It  will  thus  be  seen  that,  under  these  circumstances, 
where  a  h'eld  receives  back,  in  the  farm-yard  manure,  a 
larger  share  of  phosphate  than  it  has  lost  in  the  crops, 
the  action  of  guano  upon  it  will  grow  feebler  from  year 
to  year,  until  at  last  it  ceases  to  be  appreciable. 

But  the  case  is  very  different  as  regards  the  applica- 
tion of  guano  on  fields  to  which  a  smaller  quantity  of 
phosphates  is  returned  in  the  farm-yard  manure  than 
has  been  lost  in  the  crops,  and  that  have,  for  instance, 
been  cultivated  for  half  a  century  upon  the  farm-yard 
manuring  system.  It  has  already  been  explained,  that 
on  such  fields  certain  constituents  of  the  fodder  plants 
and  of  straw,  more  particularly  soluble  silicic  acid  and 
potash,  are  continually  increasing  in  the  arable  soil, 
whilst  by  the  export  of  corn  and  flesh  its  store  of  min- 
eral substances  is  reduced  by  the  quantity  contained  in 
the  exported  matters.  The  two  sets  of  constituents  had 
jointly  produced  the  crop.  By  taking  away  the  seed- 
constituents  a  corresponding  amount  of  the  straw  and 
fodder  constituents  was,  accordingly,  rendered  ineffec- 
tive. In  fields  of  this  description,  manuring  with  guano 
not  only  brings  up  the  amount  of  produce  to  the  former 
•Standard,  but  frequently  even  increases  it  to  a  surprising 


EEASON    OF    THE   EFFECTIVE   ACTION    OF    GUANO.       251 

extent,  when  the  soil  contains  a  large  store  of  other  as- 
similable food  elements,  which  require  only  the  presence 
of  the  guano  constituents  to  make  them  available  for 
nutrition.  In  the  increased  produce  thus  obtained, 
there  is,  of  course,  carried  off,  together  with  the  guano 
constituents,  also  a  part  of  the  store  of  the  other  food 
elements ;  and  upon  repeated  manurings  with  guaho 
the  fertilising  effect  of  that  agent  must  therefore  neces- 
sarily become  feebler  in  the  same  proportion  as  the 
quantity  of  these  other  food  elements  decreases  in  the 
ground.  The  fertilising  action  of  all  compound  ma- 
nures is  rarely  dependent  upon  one  constituent  alone  ; 
and  as  guano  contains,  in  its  ammonia  and  phosphoric 
acid,  two  food  elements,  which  require  the  presence  of 
each  other  to  be  available,  manuring  with  guano  insures 
the  action  of  the  phosphoric  acid,  because  the  particles 
of  the  latter  are  in  immediate  contact  with  ammonia 
particles,  that  are  at  the  same  time  also  available  to  the 
roots  ;  and  in  the  same  way  the  phosphoric  acid  insures 
and  increases  the  action  of  the  ammonia. 

In  a  soil  abounding  in  ammonia,  manrfring  with 
phosphates  alone  possessing  the  same  degree  of  solubil- 
ity, will  produce  the  same  effect  as  guano. 

When  ammonia  salts  fail  to  produce  any  effect  on  a 
field  whilst  guano  is  found  to  act  favourably,  there  is 
reason  to  attribute  the  beneficial  effect  of  the  guano 
principally  to  the  phosphoric  acid  in  it ;  but  in  the 
reverse  case  the  conclusion  would  not  hold  equally 
good,  because  the  salts  of  ammonia  produce  two  dif- 
ferent kinds  of  effects ;  they  may,  under  certain  circum- 
stances, considerably  increase  the  amount  of  produce, 
and  yet  the  favourable  effect  may  not  be  positively  at- 
tributed to  the  action  of  ammonia  as  such  (see  page  86). 

The  presence  in  the  soil  of  a  sufficient  quantity  of 
potash  and  silicic  acid  is  always  presupposed  when 
guano  increases  the  produce  of  corn  ;  and  on  a  soil  rich 
in  potash  and  magnesia,  the  application  of  guano  alone 
insures  a  succession  of  crops  of  such  plants,  which,  like 
potatoes,  require  for  their  growth  chiefly  potash  and 
magnesia. 

Meadows  and  corn  fields  which  gave  at  first  largp 


252  GUANO. 

crops  with  guano,  become  at  last,  by  the  continued  use 
of  this  agent,  frequently  so  drained  of  silicic  acid  and 
potash,  as  to  lose  lor  many  years  their  original  produc- 
tiveness. At  the  same  time  it  cannot  be  denied  that 
there  may  be  many  soils  which,  for  several  years,  by 
the  aid  of  guano  alone,  might  be  made  to  produce  high 
cereal  crops  before  this  state  of  exhaustion  appears  ;  but 
it  will  at  last  inevitably  come,  and  it  will  then  be  very 
difficult  to  repair  the  damage. 

In  800  cwt.  of  farm-yard  manure  with  which  a  hec- 
tare of  land  is  manured  in  a  rotation  of  crops,  the  soil 
receives  (according  to  Voelker's  analysis)  the  same 
quantity  of  phosphates  and  of  nitrogen  as  in  800  kilo- 
grammes (15*7  cwt.)  of  guano  ;  in  other  words,  there  is 
as  much  of  these  two  elements  of  food  for  plants  con- 
tained in  1  Ib.  of  the  latter  agent  as  in  50  Ibs.  of  farm- 
yard manure.  Guano,  therefore,  contains  these  ele- 
ments in  the  most  concentrated  form,  and  permits  the 
application  of  them  to  certain  parts  of  the  field  more 
conveniently  than  by  farm-yard  manure,  as  is  often  ad- 
vantageously done  after  putting  in  the  seed.  In  many 
places,  guano  is  mixed  with  gypsum  to  reduce  its  over- 
powerful  action.  The  gypsum  divides  the  guano  par- 
ticles and  causes  them  to  be  more  equally  distributed 
over  the  field ;  but  there  is  no  real  diminution  of  the 
chemical  action  of  the  ammoniacal  salts ;  the  gypsum 
decomposes  the  oxalate  and  the  phosphate  of  ammonia 
into  sulphate  of  ammonia  and  phosphate  and  oxalate  of 
lime.  The  phosphate  of- lime  formed  in  this  way  is  in 
a  state  of  infinitely  fine  division,  in  which  it  is  most 
suitable  for  the  roots  of  plants ;  however,  a  small  por- 
tion only  of  the  phosphoric  acid  is  converted  into  this 
state,  and  with  the  removal  of  the  oxalic  acid,  ceases, 
also,  the  beneficial  influence  wrhich  the  latter  exercises 
in  promoting  the  diffusion  of  the  phosphoric  acid. 

It  will,  therefore,  be  found  much  more  effective  to 
moisten  the  guano  with  water  to  which  a  little  sulphuric 
acid  has  been  added,  and  to  mix  it,  after  twenty-four 
hours,  with"  saw-dust,  turf-dust,  or  mould,  instead  of 
gypsum,  and  to  strew  this  mixture  over  the  surface  of 
the  field.  The  rain  water  dissolves  out  the  phosphat 


GUANO   AND   SULPHURIC   ACLJ. 


253 


of  ammonia,  which  slowly  sinks  into  the  ground,  and 
all  parts  of  the  soil  with  which  the  solution  comes  in 
contact  are  enriched  at  the  same  time  with  phosphoric 
acid  and  ammonia.  If  to  the  saw-dust,  turi-dust,  &c., 
gypsum  is  added,  it  decomposes  with  the  phosphate  of 
ammonia  into  very  finely-divided  phosphate  of  lime  and 
sulphate  of  ammonia,  which  are  separated  by  the  rain 
water ;  the  soluble  sulphate  of  ammonia  penetrating 
deeper  into  the  ground  and  carrying  down  with  it  a 
small  quantity  of  the  phosphate  of  lime,  whilst  the  main 
bulk  of  the  latter  is  left  on  the  top. 

On  land  poor  in  potash,  the  addition  of  wood  ashes 
to  the  guano,  moistened  with  water  and  sulphuric  acid, 
will  be  found  beneficial,  as  the  carbonate  of  potash  de- 
composes with  the  phosphate  of  ammonia  into  carbonate 
of  ammonia  and  phosphate  of  potash,  and  the  potash 
does  not  interfere  with  the  phosphoric  acid  penetrating 
into  the  soil. 

The  results  obtained,  in  the  Saxon  experiments,  by 
manuring  with  guano,  afford  a  clear  insight  into  all  the  pe- 
culiarities observed  in  the  action  of  this  manuring  agent. 

If  we  compare  the  produce  severally  obtained  by 
manuring  with  guano  and  with  farm-yard  manure  (see 
page  186),  we  are  led  to  the  following  considerations  on 
the  condition  of  the  experimental  field : — 

Manuring  with  guano. 


Cunnersdorf. 

Mausegast. 

Kotitz. 

Oberbobritzsch. 

Quantity    of   guano  ) 
applied                  •   f 

Ibs. 
879 

Ibs. 
411 

Ibs. 
411 

Ibs. 
616 

1851. 
Rye  corn  

1941 

2693 

1605 

2391 

"    straw  .      .           . 

5979 

5951 

4745 

5877 

1852. 
Potatoes                .  .      . 

17904 

17821 

19040 

13730 

185.3. 

2041 

1740 

1188 

1792 

2873 

2223 

902 

2251 

1854. 
Clover  

9280 

6146 

1256 

5044 

254 


GUANO. 


Increase  of  produce  above  the  unmanured  plot  (see  p.  186). 


Cunnersdorf. 

Mausegast. 
(1853,  barlej 
instead  of  oats.) 

Kotitz. 

Obeibobritzsch. 

Amount  of  nitrogen) 
in  the  manure  ) 

Ibs. 
49-3 

765 

Ibs. 
53-4 

456 

Ibs. 
53-4 

341 

Ibs. 
80-1 

938 

"    straw  

S028 

1369 

1732 

2862 

Potatoes  

1237 

925 

463 

3979 

22 

451 

151 

264 

"   straw  

310 

383 

455 

439 

Red  clover 

136 

608 

161 

4133 

In  Cunnersdorf,  the  increase  of  produce  obtained 
in  1851,  over  the  unmanured  field,  amounted  to — 

Corn.  Straw.       Eatio. 
Ibs.  Ibs.  Ibs. 

By  farm-yard  manure  (180  cwt.)  ...     337  1745  =  1:5 

By  guano  (379  Ibs.) 765  3028  =  1  :  3'8 

The  field  at  Cunnersdorf  was  naturally  rich  in  those 
ingredients  which  we  have  designated  as  St  (straw)  con- 
stituents (silicic  acid,  potash,  lime,  magnesia,  iron),  and 
the  increase  of  these  by  the  farm-yard  manure  aug- 
mented the  straw  at  the  expense  of  the  grain  crop. 
The  farm-yard  manure  contained  too  little  of  the  K 
(corn)  constituents  (nitrogen,  phosphoric  acid). 

This  explains  the  powerful  action  of  guano  (which 
contains  chiefly  K  constituents)  upon  this  field;  the 
increase  of  corn  by  its  means  was  more  than  double 
that  obtained  from  farm-yard  manure,  and  a  more  suit- 
able proportion  was  established  between  the.  K  and  S£ 
constituents  in  the  ground. 

At  Mausegast  the  increase  of  produce  obtained  in 
1851,  above  that  of  the  unmanured  field,  amounted  to — 

Corn.  Straw.         Eatio. 
Ibs.  Ibs.  Ibs. 

By  farm-yard  manure  (194  cwt.)  ...     345  736  =  1  :  2-1 

By  guano  (411  Ibs.) 455  1369  =  1  :  3'0 

This  field  was  richer  in  K  and  S£  constituents  than  the 


EFFECT   OF   GUANO   ON    STKAW   PRODUCE.  255 

Cunnersdorf  field,  and  contained,  already,  an  excess  of 
St  constituents.  The  K  constituents  supplied  in  the 
guano  constituted  a  much  smaller  fraction  of  the  whole 
store  already  present  in  the  field  than  was  the  case 
with  the  Cunnersdorf  field,  and  their  effect  tended 
rather  to  increase  the  produce  of  straw  than  that  of 
corn. 

The  application  of  guano  had  the  effect  of  producing 
the  same  quantity  of  straw  on  the  Cunnersdorf  as  on 
the  Mausegast  field  (5951  and  5979  Ibs.);  but  the  corn 
reaped  from  the  latter  exceeded  that  obtained  from  the 
former  by  752  Ibs.  The  Mausegast  field  was  much 
richer  in  K  constituents  than  the  Cunnersdorf  field. 

At  Kotitz  the  increase  of  produce  was — 

Corn.  Straw.       Eatio. 
Ibs.  Ibs.  Ibs. 

By  farm-yard  manure  (229  cwt.)  .  .  .     352  1006  =  1  :  2'8 

By  guano  (41  libs.) 341  1732  =  1:5 

The  effect  of  guano  upon  the  straw  produce  was  here 
out  of  all  proportion  greater  than  that  of  farm-yard 
manure,  whilst  the  produce  of  corn  was  smaller.  It  is 
quite  evident  that  one  constituent  acting  more  power- 
fully in  the  direction  of  the  formation  of  straw  was 
supplied  to  the  field  in  larger  proportion  in  the  guano 
than  in  the  farm-yard  manure.  Experiments  with 
superphosphate  (excluding  ammonia),  or  with  an  am- 
moniacal  salt  (excluding  phosphoric  acid),  would  have 
shown  to  which  of  these  two  elements  the  difference  in 
the  produce  was  owing. 

At  Oberbobritzsch  the  increase  of  produce  was — 

Corn.  Straw.      Eatio. 
Ibs.  Ibs.          Ibs. 

By  farm-yard  manure  (314  cwt.)  .  .  .     452  913  =  1:2 

By  guano  (616  Ibs.) 938  2812  =  1:3 

As  the  quantity  of  guano  used  at  Oberbobritzsch  was 
about  50  per  cent,  more  than  in  the  preceding  experi- 
ments, no  comparison  as  to  amount  can  be  made 
between  the  produce  of  this  field  and  that  of  the  others. 
What  is  again  remarkable  here  is  the  similarity  of  the 
condition  of  this  and  the  Mausegast  field;  on  both, 


256 


GUANO. 


farm-yard  manure  gave  straw  and  corn  in  the  propor- 
tion of  1*2;  guano,  in  the  proportion  of  1*3.  As 
regards  the  power  of  the  soluble  guano  constituents  to 
pass  through  the  soil,  we  find  from  these  experiments 
the  same  conditions  existing  as  with  those  of  farm-yard 
manure.  At  Cunnersdorf  and  Kotitz  the  whole  guano 
constituents  hardly  produced  any  effect  upon  the  clover 
crop ;  whilst  at  Mausegast  and  Oberbobritzsch  a  per- 
ceptible increase  was  the  result. 

Silicic  acid,  which  gives  strength  and  firmness  to 
stalks  and  leaves,  is  not  one  of  the  ingredients  of  guano  ; 
hence,  after  manuring  with  guano,  the  tendency  of  the 
cereals  to  lodge,  so  much  dreaded  by  agriculturists,  is 
observed  on  many  fields  poor  in  silicic  acid,  whilst  on 
others  abounding  in  this  substance  it  does  not  occur. 
On  many  soils  mis  tendency  may  be  cured  by  dressing 
with  lime  before  applying  the  guano  ;  and  in  other 
cases  it  may  be  lessened  "by  mixing  dung  made  from 
straw  with  the  guano. 

If  we  calculate  the  increase  in  the  produce  of 
cereals,  potatoes,  and  clover,  obtained  severally  in  the 
years  1851  to  1854,  from  100  Ibs,  of  guano  we  find 

100  Ibs.  of  guano  gave  increase  of  produce. 


Cunnersdorf. 

Mausegast. 

Kctitz. 

Oberbobritzsch. 

1851  and  1853. 
Rye  and  oats  

Ibs 
1088 

Ibs. 
646 

Ibs. 
S54 

Ibs/ 

731 

1852. 
Potatoes  

326 

225 

112 

646 

1854. 
Clover  

36 

172 

39 

670 

These  results  show  that  the  same  quantity  of  guano 
has  an  equally  dissimilar  effect  upon  different  fields  as 
farm-yard  manure,  and  that  it  is  quite  impossible  to 
draw  from  the  crops  obtained  any  inference  as  to  the 
quality  or  quantity  of  the  manuring  agent  employed  to 
produce  them.  The  field  at  Mausegast  had  received 


INCREASE   OF   PRODUCE  BY   GUANO.  257 

the  same  amount  of  guano  as  the  Kotitz  field,  both, 
accordingly,  the  same  quantity  of  nitrogen  and  phos- 
phoric acid ;  yet  in  cereals  and  potatoes  the  increase  of 
produce  was  twice  as  great,  and  in  clover  much  greater 
in  the  former  than  in  the  latter. 

How  very  little  the  crops  will  enable  us  to  draw 
comparisons  between  the  effects  of  the  several  constitu- 
ents of  one  and  the  same  manuring  agent,  may  be 
clearly  seen  from  the  results  of  the  experiments  at 
Cunnersdorf  and  Oberbobritzsch. 

At  Cunnersdorf,  100  Ibs.  of  guano  gave  an  increase 
of  produce  in  cereals,  potatoes,  and  clover,  containing — 

Phosphoric 
Nitrogen.  Potash.       acid.       Lime. 

Ibs.          Ibs.          Ibs.          Ibs. 

Increase  of  produce ...       9'2       16'1         3'5         3'6 
The  guano  contained  .  .     13'0         2'0       12'0       12'0 

More  in  the. manure.  .         3-8        —         S'5         8 '4  less  in  the  crops. 
Less  in  the  manure  ...       —      14-1         —         —  more  in  the  crops. 

At  Oberbobritzsch,  100  Ibs.  of  guano  gave  an  increase 
of  produce,  containing — 

Phosphoric 
Nitrogen.  Potash.       acid.      Lime. 

Ibs.         Ibs.         Ibs.         Ibs. 

Increase  of  produce ...     23'0       15'5         6'1       16'9 
The  guano  contained  .  .     13'0         2'0       12'0       12'0 

More  in  the  manure.  .  .        —         —        5%9         —  less  in  the  crops. 
Less  in  the  manure  ,  .  .     10-0       13'5         —        4-9  more  in  the  crops. 

The  difference  in  the  effect  produced  by  the  guano 
on  the  two  fields  is  most  strikingly  exhibited  by  these 
tables.  At  Cunnersdorf  the  produce  reaped  contained 
30  per  cent,  less,  at  Oberbobritzsch  77  per  cent,  more 
nitrogen  than  the  manure  applied. 


CHAPTEft  YIL 

POUDKETTE HUMAN   EXCREMENTS. 

Poudrette,  nature  of  ;  small  amount  of  the  food  of  plants  in  it — Human  excrement 
its  value— Construction  of  the  privies  in  the  barracks  at  Rastadt— Calculation, 
of  the  amount  of  corn  produced  by  the  excrement  collected  ;  importance  to  the 
neighbourhood— Its  eft'ect  not  impaired  by  deodorising  with  sulphate  of  iron — 
The  excrement  of  the  inhabitants  of -towns  as  manure — Its  importance. 

"pOUDKETTE,  sold  as  manure,  should  consist  simply 
-t  of  the  desiccated  excrements  of  man  made  into  a 
transportable  form.  This  is  not  the  case,  however,  as 
most  poudrettes  contain,  in  reality,  only  a  comparative- 
ly small  proportion  of  excrementitious  matter.  To 
show  this,  it  will  suffice  to  point  out  that  the  poudrette 
of  Montfaucon,  which  is  one  of  the  best  sorts,  contains 
28  per  cent.,  that  of  Dresden  from  43  to  56  per  cent., 
that  of  Frankfort  above  50  per  cent.,  of  sand.  ~No  kind 
of  poudrette  is  ever  met  with  in  commerce  containing 
more  than  3  per  cent,  of  phosphoric  acid,  and  the  same 
amount  of  ammonia.  The  construction  of  privies  in 
dwelling-houses  (at  least,  in  Germany)  does  not  make 
it  practicable  to  keep  out  the  sweepings  and  other  rub- 
bish of  the  house ;  besides,  when  emptying  the  pits,  it 
is  often  the  practice,  after  taking  out  the  fluid  contents, 
to  throw  into  the  residuary  mass  some  solid  porous 
body,  such  as  brown-coal  or  turf-dust,  to  make  it  drier 
and  more  convenient  for  removal.  All  additions  of  the 
kind,  of  course,  diminish  the  percentage  of  effective  and 
available  food  elements,  and  increase  the  costs  of  trans- 
port. The  privy  pits,  moreover,  are  but  rarely  water- 
tight, and  permit  the  greater  part  of  the  urine  and 


VALUE  OF  HUMAN  EXCKEMENTS.         259 

other  fluid  contents  to  leak  away,  thus  causing  the  loss 
of  a  good  deal  of  the  most  valuable  matter,  such  as  the 
potash  salts,  and  the  soluble  phosphates.  The  follow- 
ing statement  will  show  the  great  value  of  the  excre- 
ment of  man.  In  the  fortress  of  Rastadt  and  in  the 
soldiers'  barracks  in  Baden  generally,  the  privies  are  so 
constructed  that  the  seats  open,  through  wide  funnels, 
into  casks  fixed  upon  carts.  By  this  means  the  whole 
of  the  excrements,  both  fluid  and  solid,  are  collected 
without  the  least  loss.  When  the  casks  are  full,  they 
are  replaced  by  empty  ones.* 

The  food  of  the  soldier,  in  Baden,  consists  chiefly  of 
bread,  but  also  of  certain  daily  rations  of  meat  and 
vegetables.  As  the  body  of  an  adult  does  not  increase 
in  weight,  it  needs  no  particular  calculation  to  make 
out  that  the  collected  excrements  must  contain  the  ash- 
constituents  of  the  bread,  meat,  and  vegetables,  and 
also  the  whole  of  the  nitrogen  of  the  food. 

To  produce  a  pound  of  corn,  the  soil  has  to  furnish 
the  ash-constituents  of  that  pound  of  corn ;  if  we  sup- 
ply these  ash-constituents  to  a  suitable  field,  the  latter 
will  thereby  be  enabled  to  produce,  in  a  number  of 
years,  one  pound  of  corn  more  than  it  would  have  done 
without  this  additional  supply  of  ash-constituents.  The 
daily  ration  of  a  soldier,  in  Baden,  is  2  Ibs.  of  bread; 
the  excrements  of  the  8000  men  of  the  different  garri- 
sons contain  accordingly,  per  day,  the  ash-constituents 
and  the  nitrogen  of  16,000  Ibs.  of  bread,  which  returned 
to  the  soil  will  fully  suffice  to  reproduce  the  same  quan- 
tity of  corn  as  had  been  used,  in  form  of  flour,  to  bake 

*  The  price  of  a  cart  is  from  100  to  125  florins  =  £8  6s.  Sd.  to  £10  8s. 
4d.  It  will  last  about  five  years.  The  original  outlay  incurred  by  the 
Army  administration  in  Baden,  in  1856  and  1857-,  for  the  carts  and  casks 
amounting  to  about  £370,  was  speedily  repaid  out  of  the  proceeds  of  the 
manure. 

The  collective  number  of  the  garrisons  of  Constance,  Freiburg,  Rastadt, 
Carlsruhe,  Bruchsal,  and  Mannheim,  averages  about  8000  men.  The 
receipts  for  manure  sold  were  in  1852,  £285;  in  1853,  £315;  in  1854, 
£443  ;  1855,  £400  ;  1856,  £668  ;  185Y,  £668  ;  1858,  £680  ;  £50  or  £60 
are  to  be  deducted  from  these  receipts  annually  for  cost  of  maintenance, 
repair,  &c.,  of  the  carts,  &c.  ('  Journ.  of  the  Agrie.  Soc.  of  Bavaria,'  April 
1860.  Page  180.) 


260  POUDKETTE HUMAN   EXCKEMENTS. 

the  16,000  Ibs.  of  bread.  Beckoning  1£  Ib.  of  corn  to 
2  Ibs.  of  bread,  the  excrements  of  the  soldiers  in  the 
Grand  Duchy  of  Baden  give,  therefore,  annually,  the 
ash-constituents  required  for  the  production  of  43,760 
cwts.  of  corn. 

The  peasants  about  Rastadt  and  the  other  garrison 
towns,  having  found  out  at  last  by  experience  the  pow- 
erful fertilising  effect  of  these  excrements  upon  their 
fields,  now  pay  for  every  full  cask  a  certain  sum  (still 
rising  in  price  every  year),  which  not  only  has  long 
since  repaid  the  original  outlay,  besides  covering  the 
annual  cost  of  maintenance,  repairs,  &c.,  but  actually 
leaves  a  handsome  profit  to  the  department. 

The  results  brought  about  in  these  districts  are 
highly  interesting.  Sandy  wastes,  more  particularly  in 
the  vicinity  of  Rastadt  and  Carlsruhe,  have  been  turned 
into  smiling  corn-fields  of  great  fertility.  Assuming, 
for  the  sake  of  illustration,  that  the  peasants  had  to  fur- 
nish the  whole  corn  produced  by  means  of  this  manure, 
to  the  military  administrations  of  the  several  garrison 
towns,  there  would  thus  be  established  a  perfect  circu- 
lation of  these  conditions  of  life,  which  would  provide 
8000  men  with  bread,  year  after  year,  without  in  the 
least  reducing  the  productiveness  of  the  fields  on  which 
the  corn  is  grown,  because  the  conditions  required  for 
the  production  of  corn  being  thus  always  returned  to 
the  soil,  would  continue  to  circulate  and  yet  always  re- 
main the  same.* 

What  is  said  here  about  the  corn-constituents  ap- 
plies, of  course,  equally  to  the  constituents  of  meat  and 
vegetables,  which,  returned  to  the  field,  will  reproduce 
as  much  meat  and  vegetable  matter  as  has  been  con- 
sumed. The  same  relation  that  exists  between  the  in- 

*  When,  some  years  ago,  an  order  was  suddenly  issued  by  the  authori- 
ties of  the  city  of  Carlsruhe,  to  deodorise  and  disinfect  the  pits  and  cess- 
pools with  sulphate  of  iron,  before  being  emptied,  the  farmers  refused  at 
first  to  pay  any  longer  for  the  contents,  which  they  argued  were  by  this 
treatment  deprived  of  their  fertilising  virtue.  Experience  has  shown  that 
this  is  not  the  case,  and  the  disinfected  dung  commands  as  high  a  price 
now  as  the  article  in  its  pure  state  did  formerly.  The  dung  in  the  privy 
carts  requires  no  disinfecting. 


LOSS   OF   MANURE   BY   CARELESSNESS.  261 

habitants  of  the  barracks  in  Baden  and  the  fields  sup- 
plying them  with  bread,  exists  equally  between  the  in- 
habitants of  towns  and  the  country  around.  If  it  were 
practicable  to  collect,  without  the  least  loss,  all  the  solid 
and  fluid  excrements  of  all  the  inhabitants  of  towns,  and 
to  return  to  each  farmer  the  portion  arising  from  the 
produce  originally  supplied  by  him  to  the  town,  the 
productiveness  of  his  land  might  be  maintained  almost 
unimpaired  for  ages  to  come,  and  the  existing  store  of 
mineral  elements  in  every  fertile  field  would  be  amply 
sufficient  for  the  wants  of  the  increasing  populations. 
At  any  rate,  that  store  is,  at  present,  still  sufficient  to 
do  so,  although  the  number  of  farmers  who  take  care 
to  cover  by  an  adequate  supply  of  suitable  manures  the 
loss  of  mineral  matters  sustained  by  the  land  in  the  crops 
grown  on  it,  is  but  small  in  proportion  to  the  whole 
agricultural  population.  However,  sooner  or  later,  the 
time  will  come  when  the  deficiency  in  the  store  of  these 
mineral  matters  will  be  important  enough  in  the  eyes 
of  those  who  are,  at  present,  so  void  of  sense  as  to  be- 
lieve that  the  great  natural  law  of  restoration  does  not 
apply  to  their  own  fields  ;  and  the  sins  of  the  fathers, 
in  this  respect,  will  also  be  visited  upon  their  posterity. 
In  matters  of  this  kind,  inveterate  evil  habits  are  but 
too  apt  to  obscure  our  better  judgment.  Even  the  most 
ignorant  peasant  is  quite  aware  that  the  rain  falling 
upon  his  dung-heap  washes  away  a  great  many  silver 
dollars,  and  that  it  would  be  much  more  profitable  to 
him  to  have  on  his  fields  what  now  poisons  the  air  of 
his  house  and  the  streets  of  his  village ;  but  he  looks 
on  unconcerned,  and  leaves  matters  to  take  their  course, 
because  they  have  always  gone  on  in  the  same  way. 


CHAPTEE  YIIL 

EAKTHY     PHOSPHATES. 

High  agricultural  value  of  phosphates— Phosphates  of  commerce  ;  selection  of  the 
kind  to  be  used  dependent  on  the  object  in  view,  and  on  the  nature  of  the  soil — 
The  rapidity  and  duration  of  the  effect  of  the  neutral  and  of  the  soluble  phos- 
phate (superphosphate)  of  lime— The  Saxou  manuring  experiments. 

THE  earthy  phosphates  are  among  the  most  impor- 
tant agents  for  restoring  the  impaired  productive- 
ness of  land ;  not  that  they  influence  vegetation  in  a 
more  marked  manner  than  other  mineral  elements,  but 
because  the  system  of  cultivation  pursued  by  the  corn 
and  flesh  producing  farmer  tends  to  remove  them  from 
the  soil  in  larger  proportion  than  other  constituents. 

In  choosing  among  the  phosphates  of  commerce, 
the  farmer  should  always  keep  in  view  the  object  which 
lie  intends  to  accomplish,  as  some  sorts  will  answer 
better  for  certain  purposes  than  others. 

The  so-called  superphosphates  are  commonly  phos- 
phates to  which  a  certain  quantity  of  sulphuric  acid 
has  been  added,  to  convert  the  insoluble  neutral  lime 
salt  into  a  soluble  acid  salt.  When  mixed  with  a  salt 
of  ammonia  and  a  salt  of  potash,  they  are  often  called 
guano  or  ammoniacal  superphosphates.  A  good  super- 
phosphate generally  contains  from  10  to  12  per  cent, 
of  soluble  phosphoric  acid.  On  land  poor  in  clay  and 
lime  the  superphosphates  are  particularly  suitable  for 
supplying  the  upper  layer  of  the  soil  with  phosphoric 
acid.  Their  effect  upon  the  produce  of  potatoes  and 
of  cereals  on  such  fields  is  equal  to  that  of  Peruvian 
guano.  For  turnips  and  rape,  which  derive  advantage 


PROPERTIES   OF   BONE-DUST.  263 

from  the  presence  of  sulphuric  acid,  they  have  a  special 
value.  On  chalky  soils,  the  free  phosphoric  and  sul- 
phuric acids  are  immediately  neutralised,  by  which  they 
are  deprived  of  one  of  their  essential  properties,  viz., 
their  ready  diffusibility,  which  renders  them  so  valuable 
a  manure  for  other  soils. 

Among  the  neutral  phosphates  bone-dust  holds  the 
first  rank.  When  bones  are  exposed,  under  high  pres- 
sure, to  the  action  of  steam,  they  lose  their  toughness, 
and  swell  up  into  a  soft  gelatinous  mass,  which,  after 
drying,  may  be  readily  ground  to  a  fine  powder.  In 
this  form  it  spreads,  with  great  rapidity,  through  the 
soil ;  it  dissolves  in  water  to  a  small  but  perceptible 
extent,  without  requiring  the  presence  of  any  other 
solvent.  What  dissolves,  under  these  circumstances, 
in  water,  is  a  combination  of  gelatine  with  phosphate 
of  lime,  which  is  not  decomposed  by  the  arable  earth, 
and  therefore  penetrates  deep  into  the  ground — a  prop- 
erty wanting  in  the  superphosphate.  In  the  moist 
ground,  however,  the  gelatine  speedily  putrefies,  being 
converted  into  ammonia  compounds,  and  the  phosphate 
of  lime  is  then  retained  by  the  arable  earth.  Bone-dust 
is  the  agent  best  adapted  to  supply  phosphate  of  lime 
to  the  deeper  layers  of  the  arable  soil,  for  which  pur- 
pose the  superphosphates  are  not  suitable.  Bone-earth, 
or  bone-ash,  is  the  name  applied  to  bones  freed,  by  cal- 
cination, from  the  glue  or  gelatinous  part.  The  animal 
charcoal  of  sugar  refineries  belongs  to  this  category. 
It  must  be  reduced  to  the  finest  powder  to  render  it 
fully  available  for  manuring  purposes.  To  effect  its 
more  speedy  distribution  through  the  soil,  the  presence 
of  a  decaying  organic  substance  is  necessary  to  supply 
the  carbonic  acid  required  for  its  solution  in  rain  water. 
An  excellent  way  is  to  mix  the  powder  with  farm-yard 
manure  and  let  the  mixture  ferment.  Among  the  phos- 
phates of  commerce,  the  guano  coining  from  the  Baker 
and  Jarvis  Islands  are  distinguished,  before  others,  by 
their  acid  reaction  and  greater  solubility.  They  con- 
tain only  a  small  quantity  of  an  azotised  substance,  no 
uric  acid,  and  small  proportions  of  nitric  acid,  potash, 


264: 


EARTHY   PHOSPHATES. 


magneisa,  and  ammonia.  The  Baker  guano  contains 
as  much  as  80  per  cent.,  the  Jarvis  gua.no  33  or  34  per 
cent,  of  phosphate  of  lime ;  the  latter  having,  besides, 
44  per  cent,  of  gypsum.  In  diffusibility,  these  guanos, 
when  equally  finely  powdered,  approach  nearest  to  bone- 
dust:  their  condition  also  enables  the  farmer  who  wishes 
to  accelerate  their  action,  to  convert  them  most  readily 
into  superphosphates  (100  parts  by  weight  of  Baker 
guano  require  20  to  25  per  cent,  of  concentrated,  or  30 
to  40  per  cent,  of  the  lead  chamber  sulphuric  acid). 

The  influence  of  these  neutral  phosphates  upon  the 
produce  of  a  field  is  generally  less  marked  in  the  first 
than  in  the  following  years,  as  it  takes  a  certain  time 
to  effect  their  diffusion  through  the  soil.  The  speedier 
or  slower  manifestation  of  their  action  upon  a  field 
depends,  in  a  great  measure,  upon  the  state  of  fine- 
ness of  the  powder,  to  which  they  have  been  reduced, 
the  greater  or  less  porosity  of  the  soil,  the  presence  in 
it  of  decaying  matters,  and  careful  tillage  ;  but,  under 
any  circumstances,  they  require  a  certain  store  of  sol- 
uble silicic  acid,  and  of  soda  and  potash  in  the  soil. 

The  subjoined  table  giving  the  produce  obtained, 
in  the  years  1847-50,  by  H.  Zenker,  at  Klein wolmsdorf, 
in  Saxony,  shows  the  difference  between  guano  and 
bone-dust  as  regards  rapidity  and  duration  of  action. 
In  the  first  year  the  guano  gave  the  larger  produce, 
which  became  smaller  in  each  following  year ;  in  the 
first  year  the  crop  from  the  bone-dust  was  smaller,  but  in 
the  succeeding  years  the  increase  was  most  remarkable. 


Bone-dust  (822  Ibs.). 

Guano  (411  Ibs.). 

Corn. 

Straw. 

Corn. 

Straw. 

1847. 

Ibs. 
2798 

2862 
1591 
1351 

Ibs. 
4831 

3510 
5697 

2768 

Ibs. 
2951 

2484 
1095 

732 

Ibs. 
4711 

3201 
4450 
2481 

1848. 
Barley  

1849. 
Vetches  

1850. 
Winter  corn  

PRODUCE   FKOM   GUANO  AND   BONE-DUST. 


265 


The  411  Ibs.  guano  contained  53,  and  the  total  pro- 
duce 271  Ibs.  of  nitrogen,  or  very  nearly  five  times 
more.  The  bone-dust  contained  37  Ibs.  of  nitrogen, 
whereas  in  the  total  produce  there  were  342  Ibs.,  or 
nearly  nine  times  more.  The  bone-dust  gave  in  the 
crops  altogether  71  Ibs.  of  nitrogen  more  than  the  guano. 
Between  the  quantity  of  nitrogen  in  the  manure  and 
the  amount  of  the  crops  reaped,  there  is,  therefore,  no 
connection  whatever. 

In  the  Saxon  experiments,  the  plots  manured  with 
bone-dust  gave  the  following  results  : — 
Manuring  with  tone-dust. 


Cunnersdorf. 

Kotitz. 

Oberbobritzsch. 

Mausegast. 

Quantity  of  bone-dust) 
used  .        .       .        .  } 

Ibs. 
823 

Ibs. 
1233 

Ibs. 
1644 

Ibs. 
892 

1851. 

1399 

1429 

2230 

1982 

"    straw  

4167 

3707 

5036 

4365 

1852. 
Potatoes 

18250 

19511 

11488 

19483 

1853. 
Oat  corn  

2346 

1108 

1718 

1405 

"   straw  

3105 

1224 

1969 

1905 

1854. 
Clover  

10393 

2186 

7145 

5639 

Increase  of  produce  over  the  unmanured  field  (see  p.  186). 


Cunnersdorf. 

Kotiti. 

Oberbobritzsch. 

Mausegast. 
(1853,  barley 
instead  of  oats.) 

1851. 

Ibs. 
227 

Ibs. 
165 

Ibs. 

777 

Ibs. 

1216 

694 

2021 

__•_ 

1852. 
Potatoes  

1583 

934 

1737 

2587 

1853. 
Oat  corn                   .... 

327 

190 

116 

542 



157 

65 

1854. 
Clover  

1249 

1091 

6234 

101 

12 


266 


EARTHY    PHOSPHATES. 


The  field  at  Kotitz  got  50  per  cent,  more  bone-dust 
than  the  Ciinnersdorf  field  ;  yet  its  produce  of  all  the 
crops  was  lower  than  that  of  the  latter.  The  field  at 
Oberbobritzsch  got,  in  1851,  twice  the  quantity  of 
manure  that  was  applied  to  the  Ciinnersdorf  field  ;  the 
result  was,  in  the  first  year,  an  increase  of  corn  of  250 
per  cent.,  and  of  straw  of  66  per  cent,  more  on  the  for- 
mer than  on  the  latter.  In  the  third  year,  however, 
the  increase  of  produce  of  oats,  both  in  grain  and  straw, 
was  considerably  larger  at  Cunnersdorf  than  at  Ober- 
bobritzsch. 

The  most  curious  part  of  the  results  is  the  great 
difference  in  the  increase  of  the  produce  of  clover  on 
the  several  fields ;  from  the  field  at  Oberbobritzsch 
nearly  six  times  as  much  clover  was  obtained  as  from 
that  at  Kotitz,  although  the  former  had  received  only 
one-fourth  more  bone-dust  than  the  latter. 

A  glance  at  the  table  shows  that  in  the  experiments 
at  Cunnersdorf,  Kotitz,  and  Oberbobritzsch,  the  quan- 
tities of  bone-dust  severally  applied  as  manure  were  as 
1 :  1J :  2.  A  'comparison  of  the  increase  of  produce 
obtained  by  bone-earth,  just  as  in  the  case  of  guano 
and  farm-yard  manure,  again  demonstrates  that  there 
is  no  connection  or  relation  of  dependence  between  the 
amount  of  manure  and  the  increase  of  the  crops. 

100  Ibs.  lone-dust  gave  increase  of  produce — 


• 

Cunnersdorf. 

Kotitz. 

'  Oberbobritzsch. 

1851  and  1853. 
Rye  and  oats  

Ibs. 
280-8 

Ibs. 
40-1 

Ibs. 
191 

1852. 
Potatoes  

192 

75 

105 

1854. 
Clover  

152 

96 

380 

CHAPTER  IX. 

GROUND     KAPE-CAKE. 

Nature  and  composition  of;  the  diffusibility  of  its  constituents  in  the  Boll  is  com- 
paratively great— Its  importance  as  a  manuring  agent  is  small— The  Saxon 
agricultural  experiments  with  rape-cake — The  inferences  from  them. 

THE  residuary  mass  left  by  rape-seed  after  the  extrac- 
tion of  the  iatty  oil  from  it  by  the  press,  contains  a 
large  proportion  of  a  matter  abounding  in  nitrogen, 
which  is  nearly  related  to  the  casein  in  milk.  In  addi- 
tion to  this  substance,  it  contains  the  same  incombusti- 
ble or  ash-constituents  as  the  ashes  of  seeds.  The  rape- 
seed  ash  consists  of  phosphates,  and  differs  but  little  in 
composition  from  the  ash  of  the  grain  of  rye ;  phos- 
phates of  the  alkalies  and  phosphates  of  magnesia  pre- 
dominate in  it.  There  is  no  great  error  made  in  assum- 
ing that  in  100  Ibs.  of  rape-cake  a  field  receives  the  same 
amount  of  the  incombustible  constituents  of  rye  grain 
as  is  contained  in  250  to  300  Ibs.  of  the  latter.  . 

The  azotised  matter  in  rape-cake  powder  is  slightly 
soluble  in  water,  but  its  solubility  increases  with  inci- 
pient putrefaction ;  hence  the  nutritive  matters  con- 
tained in  it  are  much  more  widely  diffused  in  the  ground 
than,  for  instance,  the  principal  ingredients  of  guano, 
ammonia,  and  phosphoric  acid,  which  are  absorbed,  as 
soon  as  dissolved,  by  the  earth  particles  that  come  in 
contact  with  them.  Whereas  with  rape-cake  powder 
this  takes  place  only  after  its  azotised  matter  has  been 
completely  decomposed,  and  its  nitrogen  converted 
into  ammonia.  This  decomposition  proceeds,  however, 


268 


GROUND   KAPE-CAKE. 


pretty  fast,  and  the  effect  of  rape-cake  makes  itself  felt, 
accordingly,  in  the  very  first  year  of  its  application. 

It  is  owing  to  this  greater  diffusibility  of  its  con- 
stituents in  the  earth  that  rape-cake  appears  to  exer- 
cise a  somewhat  more  powerful  effect  upon  vegetation 
than  guano,  for  instance,  with  an  equal  amount  of  phos- 
phoric acid. 

However,  rape-cake  holds  no  very  important  rank 
as  a  manure,  simply  because  very  few  agriculturists 
are  in  a  position  to  procure  any  considerable  quantity 
of  it  for  manuring  purposes.  Besides,  when  its  great 
value  as  an  article  of  food  for  cattle  shall  be  more  uni- 
versally known  and  acknowledged,  the  increasing  price 
will  restrict,  still  more,  its  use  as  a  manuring  agent ; 
the  more  so  since  the  excrements  of  animals  fed  upon 
rape-cake  contain  the  principal  bulk  of  the  constituents 
to  which  is  due  its  efficacy  as  a  fertilising  agent. 

The  following  results  were  obtained,  in  the  Saxon 
experiments,  by  manuring  with  ground  rape-cake  : — 


Cunnersdorf. 

Mausegast. 

Kotitz. 

Oberbobritzsch. 

Mfinure         .          .    .  •  . 

Ibs. 
1614 

Ibs. 
1855 

Ibs. 
1849 

Ibs. 

3288 

1851. 
Rye  corn          

1868 

2645 

1578 

1946 

5699 

5998 

4218 

4475 

1852. 

17374 

18997 

19165 

10442 

1853. 
Oat  corn  

2052 

barley 
1619 

1408 

1517 

2768 

2298 

1550 

1939 

1854. 
Clover  

9143 

6659 

981 

2105 

RAPE-CAKE  AS  A  MANURE. 
Increase  of  produce  over  the  unmanured  field  (see  p.  186). 


Cunnersdorf. 

Mausegast. 

Kutitz. 

Oberbobritzsch. 

Amount  of  nitrogen  ) 
in  manure  ) 

Ibs. 
78-9 

Ibs. 
88'8 

Ibs. 
89 

Ibs. 
157-8 

1851. 

692 

407 

314 

493 

"    straw  

2748 

1416 

1205 

1460 

1852. 
Potatoes  

707 

2101 

588 

691 

1853. 
Oat  corn  

33 

330 

69 

"   straw  

205 

458 

193 

127 

1854. 
Clover-hav  

1121 

1194 

Here,  again,  we  see,  as  in  the  case  of  farm-yard 
manure,  guano,  and  bone-dust,  that  on  no  one  field  did 
the  effect  of  the  rape-cake  bear  any  visible  proportion 
or  relation  to  the  quantity  used. 

1000  Us.  of  ground  rape-cake  gave  increase  of  produce — 


Cunnersdoi  f. 

Mausegast. 

Kotitz. 

Oberbobritzsch. 

1851. 
Rye  corn  and  straw  .  .  . 

Ibs. 
2130 

Ibs. 
989 

Ibs. 
820 

Ibs. 

594 

1853. 
Oat  corn  and  straw.  .  .  . 

147 

424 

141 

39 

1852. 
Potatoes  

438 

1132 

318 

210 

1854. 
Clover-hay  

604 

332 

These  experiments  are  interesting  in  reference  to 
the  effect  of  the  nitrogen  supplied  in  the  manure.  A 
comparison  of  the  increase  of  produce  obtained  at  Ober- 
bobritzsch, severally  by  guano  and  ground  rape-cake, 
gives  the  following  result  in  this  respect : — 


270  GKOTJND   RAPE-CAKE. 

Oberbobritzsch. 

611  Ibs.  guano  8288  Ibs.  ground  rape-cake 

=  80  Ibs.  nitrogen  =  157'8  Ibs.  nitrogen 

and  74  Ibs.  aud  39'5  Ibs. 

phosphoric  acid.  phosphoric  acid. 

1851  and  1853.  Rye  and  oats 4503  Ibs.  2069  Ibs. 

1852.  Potatoes 3979  "  691  " 

1854.  Clover-hay 4133  "  1194  " 

The  one  field  at  Oberbobritzsch  received  in  the  ground 
rape-cake  nearly  double  the  quantity  of  nitrogen  that 
the  other  got  in  the  guano,  and  the  difference  in  the  prod- 
uce of  the  two  is  in  the  highest  degree  striking. 
In  the  two  experiments — 

In  the  In  the 

guano.  rape-cake. 

The  nitrogen  in  the  manures  was  as 1  :  2 

In  the  produce  it  was : 

"      cereals,  as 2  :  1 

"      potatoes,  as 5'7  :  1 

"      clover,  as   3'4  :  1 

The  effect  of  the  nitrogen  in  the  guano  was,  accord- 
ingly, in  the  cereals  four  times,  in  the  potatoes  twelve 
times,  and  in  the  clover  seven  times,  greater  than  that 
of  the  nitrogen  in  the  rape-cake. 

Upon  comparing  the  increase  of  produce  with  the 
amount  of  phosphoric  acid  in  the  two'manures,  we  find 
that  this  increase  appears  to  bear  some  proportion, 
though  yet  by  no  means  a  definite  one,  to  the  amount 
of  phosphoric  acid  severally  contained  in  them. 

The  general  results  of  the  experiments  made,  in  a 
four  years'  rotation,  on  four  different  fields  at  Cunners- 
dorf,  Mausegast,  Kotitz,  and  Oberbobritzsch,  may  be 
summed  up  as  follows  : — 

The  48  harvests  from  the  unmanured  plots  and  from 
those  manured  severally  with  bone-dust,  guano,  and 
ground  rape-cake,  gave  in  rye  grain  and  straw,  in  po- 
tatoes, in  oats  grain  and  straw,  and  in  clover,  by  manur- 
ing with — x 


SUMMARY   OF  RESULTS.  271 

Ground 
Bone-dust.        Guano.          rape-cake. 

Ibs.  Ibs.  IDS. 

Total  amount  of  nitrogen  in  crops ...     1170  1139  1046 

Total  amount  of  nitrogen  in  crops  )        Q10  Q10  910 

from  unmanured  plots f 

Increase  of  nitrogen  over  the  un-  )        HQQ  229  136 

manured  plots J 

The  manure  contained  nitrogen 207  236  415 

More  than  in  manure 53        less     7      less  279 

The  manure  poorest  in  nitrogen  (the  bone-dust)  thus 
actually  gave  the  highest,  and  the  one  richest  in  nitro- 
gen (the  rape-cake)  the  lowest,  amount  of  that  element 
in  the  produce. 

To  100  Ibs.  nitrogen  in  the  manure,  there  was  ob- 
tained of  that  element  in  the  increased  produce — 

By  bone-dust 125  Ibs. 

"  guano 97    " 

"  rape-cake 32   " 

The  amount  of  phosphoric  acid  in  the  crops  was 
from — 

Ground 

Bone-dust       Guano.       rape-cake.  Unmanured. 
Ibs.  Ibs.  Ibs.  Ibs. 

Phosphoric  acid 361  362  338  292 

The  manure  contained 1102  288  86  — 

The  fields  gained 741  —  —  — 

Thefieldslost —  74  252  292 


CHAPTEE   X. 

WOOD-ASH. 

The  amount  of  the  food  of  plants  in  it— Box-wood  ash  gives  only  the  half  of  its 
potash  readily  to  water- Convenience  in  mixing  Wood -ash  with  earth- before 
applying  it— Lixiviated  ash,  its  value— Proper  mode  of  applying  ashes  as  a 
manure. 

TT  has  already  been  stated  that  the  proportion  of  pot- 
J-  ash  is  very  dissimilar  in  different  wood-ashes  ;  those 
from  hard  wood  being  generally  richer  in  that  sub- 
stance than  those  from  soft  wood.  The  ash  of  beech- 
wood  gives  up  to  water  the  one-half  of  the  potash  in  it, 
in  the  form  of  carbonate  of  potash,  the  other  half  remain- 
ing in  combination  with  carbonate  of  lime,  in  a  com- 
pound which  is  only  very  slowly  decomposed  by  cold 
water.  The  ash  of  pine-wood  generally  contains,  like 
tobacco-ash,  a  larger  proportion  of  lime,  so  that  cold 
water  often  seems  to  fail  altogether  in  dissolving  any 
carbonate  of  potash  out  of  it.  However,  the  continued 
action  of  water  succeeds  always  in  gradually  extracting 
from  all  these  ashes  the  whole  of  the  potash  ;  and  since 
they  can  be  easily  ploughed  deeply  in,  they  are  suited 
better  than  all  other  potash  compounds  to  enrich  with 
that  alkali  the  deeper  layers  of  the  arable  soil.  With 
wood-ashes  that  part  readily  with  their  potash  to  water, 
it  will  be  found  useful  to  mix  the  ash,  before  applying 
it,  with  an  earth  that  absorbs  potash,  adding  so  much 
of  the  latter  that  water  poured  upon  the  mixture  will 
no  longer  turn  reddened  litmus-paper  blue.  This  oper- 
ation of  mixing  can  best  be  performed  on  the  field  itself. 
Wood-ash  which  has  been  extracted  with  water, 


APPLICATION  OF  ASHES  AS  A  MANURE.  273 

such,  for  instance,  as  the  residue  left  in  preparation  of 
potash,  possesses  for  many  fields  a  high  value  as  a 
manuring  agent,  not  only  on  account  of  the  potash 
always  present  in  it,  but  also  of  the  phosphate  of  lime 
and  soluble  silicic  acid  it  contains. 

As  the  upper  layers  of  our  corn-fields  contain  already 
naturally  an  excess  of  potash,  in  proportion  to  the  other 
food  elements,  ash-manuring,  when  confined  to  the  sur- 
face soil,  rarely  exercises  a  lasting  effect ;  but  where  the 
ash  is  carried  down  to  the  proper  depth,  it  affords  an 
excellent  means  of  obtaining  permanent  crops  of  clover, 
turnips,  or  even  potatoes.  Intelligent  manufacturers 
of  beetroot  sugar  use  with  great  success  the  residuary 
matter  from  the  distillation  of  their  molasses,  which 
contains  all  the  potash-salts  of  the  beetroot,  for  manur- 
ing their  fields,  to  restore  to  them  the  potash  removed 
in  the  beetroot-crops. 

12* 


CHAPTER  XL 

AMMONIA  AND  NITRIC   ACID. 

Source  of  the  nitrogen  of  plants— Amount  of  ammonia  and  nitric  acid  in  rain  and 
dew  :  Bineau,  Boussingault,  Knop— Quantity  of  ammonia  in  the  air— Quantity 
of  nitrogenous  food  brougllt  to  the  soil  yearly  by  rain  and  dew  ;  more  present 
in  the  soil  than  is  removed  by  the  crops — The  general  reason  for  decrease  of 
productive  power  in  soils— Classification  of  manures  according  to  the  amount 
of  nitrogen  ;  assimilable  and  sparingly  assimilable  nitrogen  ;  the  nitrogen 
theory  ;  only  ammonia  according  to  this  theory  is  wanting ;  resemblance  to 
the  humus  theory— Manuring  experiments  with  compounds  of  ammonia  by 
Schattenmann,  by  Lawes  and  Gilbert,  by  the  Agricultural  Union  of  Munich, 
and  by  Kuhlmann— The  efficacy  of  a  manure  is  not  in  proportion  to  its  amount 
of  nitrogen  :  experiments — Large  amount  of  nitrogen  in  soils  ;  the  experiments 
of  Schmid  and  Pierre  ;  the  arable  surface  soil  contains  most  nitrogen— Form 
of  the  ammonia  in  the  soil  ;  Mayer's  experiments — Comportment  of  soil  and 
farm-yard  manure  with  the  alkalies— The  ineffective  nitrogen  of  the  soil  made 
effective  by  the  supply  of  ash-constituents  that  are  wanting— Progress  in  ag- 
riculture impossible  if  dependent  on  a  supply  of  ammoniacal  compounds  ;  re- 
sults of  Lawes'  expenmen  twith  salts  of  ammonia— The  artificial  supply  of 
ammoniacal  manures  contrasted  with  the  crops  produced  and  the  increase  of 
population — Increase  of  nitrogenous  food  by  natural  means  ;  formation  of 
nitrite  of  ammonia  by  oxidation  in  the  air  according  to  Schonbeim — Supply  of 
food  in  excess  necessary  to  produce  corn-crops  ;  reasons — How  the  necessary 
excess  of  nitrogenous  food  for  corn  may  be  obtained  from  natural  sources — The 
supply  of  nitrogen  in  farm-yard  manure  in  the  Saxon  experiments  correspond- 
ed to  the  crop  of  clover-hay — Loss  of  nitrogen  in  lime  soils  by  oxidation ; 
utility  of  a  supply  of  nitrogen  to  such  soils — Effect  of  nitrogenous  food  on  the 
aspect  of  young  plants  ;  on  potatoes — Empirical  and  rational  systems  of  agri- 
culture. 

FROM  the  results  of  a  series  of  most  careful  observa- 
tions extending  over  a  number  of  years  made  by 
Bineau  in  different  parts  of  France  on  the  amount  of 
ammonia  and  nitric  acid  in  rain-water,  it  appears  that 
there  fell  annually  upon  the  area  of  a  hectare  (—  2£ 
acres)  27  kilogrammes  (=  59  Ibs.)  of  ammonia  (=  22 
kilo.  =  48  Ibs.  nitrogen),  and  34  kilogrammes  (=  75 
Ibs.)  of  nitric  acid  (=5  kilo.  =  11  Ibs.  nitrogen) ;  alto- 
gether, therefore,  27  kilo,  or  54  Zollv.  Ibs.  (—  59  Ibs. 
Eng.)  of  nitrogen. 


AMMONIA   CONVEYED   IN   KAIN   AND   DEW.  275 

For  an  English  acre  this  makes  21-9  Zollv.  Ibs.  (=  24: 
Ibs.  Eng.),  and  for  a  Saxon  acre  30  Zollv.  Ibs.  These 
numbers  nearly  coincide  with  the  observations  of  Bous- 
singault and  Knop. 

The  yearly  average  quantity  of  rain  falling  in  vari- 
ous districts,  according  to  the  position  and  elevation  of 
the  localities,  is  very  unequal ;  and  investigations  have 
shown  that  the  amount  of  ammonia  and  nitric  acid  con- 
tained in  rain-water  bears  an  inverse  proportion  to  the 
quantity  of  rain.  In  districts  where  the  rain  falls  more 
seldom  or  less  in  quantity,  the  water  is  richer  in  these 
constituents  than  in  more  rainy  districts.  According 
to  Boussingault,  dew  is  richest  in  ammonia ;  according 
to  Knop,  not  richer  than  rain-water.  (See  his  valuable 
memoir  in  the  8  hefte  der  *  Landw.  Versuchstat.  in 
Sachsen.')  But  plants  receive  ammonia  and  nitric  acid 
not  merely  by  means  of  rain-water  derived  from  the 
ground  and  in  dew,  but  also  directly  from  the  atmos- 
phere. The  experiments  of  Boussingault  ('  Annal.  de 
Chem.  et  de  Phys.,'  3  ser.  t.  liii.)  leave  no  doubt  what- 
ever with  regard  to  the  constant  presence  of  ammonia 
in  the  air.  In  a  kilogramme  of  the  following  sub- 
stances heated  to  redness,  he  found  these  quantities  of 
ammonia,  after  three  days'  exposure  to  the  air  upon 
porcelain  plates : — 

In  1  kilo,  quartz-sand 0'60  milligr.  ammonia 

"  1  "      bone-ash     0'4Y  " 

"  1   "       charcoal 2'9  " 

Although  we  can  estimate  with  tolerable  certainty 
the  quantity  of  ammonia  and  nitric  acid  which  a  field 
annually  receives  in  rain-water,  yet  the  determination 
of  the  same  in  the  dew  which  moistens  plants  is  not 
practicable.  Just  as  little  can  we  discover  how  much 
ammonia  or  nitric  acid  is  received  by  plants  directly 
from  the  air,  simultaneously  with  carbonic  acid. 

In  the  elevated  plateaus  of  Central  America,  where 
it  scarcely  ever  rains,  the  cultivated  and  wild  plants 
receive  their  nitrogenous  food  only  from  the  dew  or 
directly  from  the  air ;  and  we  may  assume,  without 


276 


AMMONIA   AND   NITRIC    ACID. 


risk  of  error,  that  the  plants  which  grow  in  the  culti- 
vated fields  of  Europe  have  as  much  ammonia  and  nitric 
acid  furnished  to  them  by  the  air  and  the  dew,  as  is  con- 
veyed to  them  in  rain-water.  A  sandy  plain,  where  no 
plants  grow,  receives  from  the  rain  as  much  ammonia 
and  nitric  acid  as  a  cultivated  field  ;  but  the  latter  de- 
rives a  greater  quantity  through  the  plants,  and  more 
from  the  leafy  plants,  than  from  those  which  are  poor 
in  leaves.  Let  us  assume  that  in  the  Saxon  experi- 
ments the  cereal  plants,  potatoes,  and  clover,  raised 
upon  the  unmanured  land,  derived  the  whole  of  their 
nitrogen  from  the  ground,  and  that  nitrogenous  food 
had  not  been  received  either  from  the  air  or  from  the 
dew ;  then  the  profit  and  loss  of  the  field  in  nitroge- 
nous nutriment  (according  to  the  assumptions  made  p. 
220,  that  TV  of  the  nitrogenous  constituents  in  clover 
and  potatoes  were  carried  off  in  the  form  of  cattle), 
may  be  thus  represented  : — 

The  field  at  Cunnersdorf. 


Produced 
altogether. 

Nitrogen. 

Lost  by 
crop  sold. 

Nitrogen. 

Gained  by 
rain. 

Nitrogen. 

1851. 
Rye  corn 

Ibs. 
1176 

Ibs. 
22*4 

Ibs. 
22  '4 

Ibs. 

"   straw  

2951 

10'6 

1852. 
Potatoes     • 

16667 

69*8 

6*9 

1853. 
Oat  corn  

2019 

30-9 

30'0 

2563 

6*6 

1854. 

9144 

202'1 

20*2 

79-5 

120 

At  the  beginning  of  the  fifth  year  the  field  was  therefore  richer, 

in  nitrogen,  by 40'6 


PRECONCEIVED   NOTIONS. 
The  field  at  Mdusegast. 


277 


Lost  by  crop  sold. 
Nitrogen 

Gained  by  rain. 
Nitrogen. 

1851. 
Eve 

Ibs. 
42-7 

7 
22-2 

12-2 

84-1 
by      .        . 

Ibs. 

120 
35*9 

1852. 

1853. 
Barley  ,  

1854. 

In  1855  the  field  was  richer  in  nitrogen 

It  is  hardly  necessary  to  carry  this  calculation  any 
further  ;  for  all  give  the  same  result,  viz.  that  even  on 
the  most  unfavourable  supposition,  a  field  receives 
back,  by  the  rain  alone,  actually  more,  certainly  not 
less,  nitrogenous  nutriment,  than  it  loses  in  the  ordi- 
nary course  of  agriculture. 

This  fact  may  well  justify  the  assertion  that  a  far- 
mer need  trouble  himself  as  little  about  a  compensating 
supply  of  nitrogen,  as  of  carbon.  Both  are,  in  fact, 
originally  constituents  of  the  air,  or  capable  of  again 
becoming  air  constituents,  and  are  in  the  circulation  of 
life  inseparable  from  one  another. 

From  the  presence  of  ammonia  and  nitric  acid  in 
rain-water  we  are  led  to  infer  that  a  source  of  nitrogen 
exists,  which  without  the  aid  of  man,  supplies  plants 
with  this  necessary  nutriment.  "With  regard  to  the 
other  nutritive  substances,  such  as  phosphoric  acid  and 
potash,  which  of  themselves  are  not  movable,  this  res- 
toration from  natural  sources  does  not  exist.  Hence, 
we  might  have  supposed,  that  when  inquiry  was  made 
as  to  the  causes  which,  in  consequence  of  cultivation, 
diminish  the  productive  power  of  land,  the  reason  of 


278  AMMONIA   AND   NITEIC   ACID. 

such  decrease  would  first  and  chiefly  have  been  sought 
in  those  nutritive  substances  which  are  of  themselves 
immovable,  and  not  in  those  which  possess  the  power 
of  circulation  ;  especially  when  it  was  ascertained  that 
part  at  least  of  the  latter  spontaneously  came  back  to 
the  field  every  year.  But  at  every  stage  in  the  devel- 
opement  of  a  science,  preconceived  ideas  will  for  a  time 
assert  their  sway  ;  and  such  is  the  case  with  those  no- 
tions which  ascribe  to  nitrogen  a  preeminent  impor- 
tance in  the  cultivation  of  land. 

In  the  consideration  of  a  natural  phenomenon,  and 
in  the  investigation  of  its  causes,  we  cannot  tell  at  first 
whether  it  be  simple  or  compound  ;  whether  it  be  due 
to  one  or  to  several  causes  ;  hence  we  are  led  to  attrib- 
ute the  results  to  those  alone  which  vxe  first  discovered 
in  operation.  No  long  time  ago,  people  believed  that 
all  the  conditions  of  growth  lay  in  the  seed  alone  ;  then 
they  found  that  water,  and  next  that  the  air,  had  a 
very  decided  influence ;  bye-and-bye  they  ascribed  to 
certain  organic  remains  in  the  ground,  a  most  impor- 
tant part  in  the  fertility  of  the  soil.  When  at  length 
they  discovered  that,  among  all  the  substances  used  for 
manure,  the  excrements  of  animals  and  the  parts  and 
constituents  of  animals,  surpassed  all  the  rest  in  opera- 
tive power ;  when,  too,  chemical  analysis  had  shown 
that  nitrogen  was  the  chief  element  in  these  substances, 
it  is  not  surprising  that  nitrogen  was  then  esteemed  the 
sole,  and  afterwards  the  principal,  agent  in  manure. 

This  process  of  reasoning  is  in  accordance  with  na- 
ture, and  cannot  be  found  fault  with.  At  that  time,  it 
was  not  known  that  the  ash-constituents  of  plants,  pot- 
ash, lime,  and  phosphoric  acid,  play  as  important  a 
part  as  nitrogen  in  the  vital  processes  of  plants  ;  nay, 
not  even  an  idea  had  been  formed  of  the  manner  in 
which  the  nitrogen  of  nitrogenous  compounds  operates. 
Men  simply  held  by  the  fact  that  horn,  claws,  blood, 
bones,  urine,  the  solid  excrements  of  animals  and  men, 
exerted  a  favourable  influence ;  while  woody  sub- 
stances, sawdust  and  similar  materials,  had  no  effect, 
or  as  good  as  none.  If  in  the  one  case  the  presence  of 


THE   NITROGEN   THEORY.  279 

nitrogen  was  the  reason  of  activity,  so  in  the  other  case 
the  want  of  nitrogen  caused  the  want  of  activity ;  in 
short,  by  the  operation  of  nitrogen  all  facts  seemed  to 
be  harmonised  and  explained. 

If  the  nitrogenous  manures  depended  for  their  ac- 
tivity upon  the  nitrogen  which  they  contained,  it  fol- 
lowed necessarily  that  all  of  them  could  not  possess  the 
same  value  for  the  farmer,  because  they  did  not  all 
contain  the  same  amount  of  nitrogen  ;  those  which  had 
more  of  this  substance  were  manifestly  more  valuable 
than  those  which  had  less.  The  amount  of  nitrogen 
was  easily  determined  by  chemical  analysis ;  hence 
arose  the  idea  to  draw  up  for  the  benefit  of  farmers  a 
list  of  manures  with  a  figure  attached  to  each  showing 
its  relative  value  ;  those  which  were  most  abundant  in 
nitrogen  were  considered  the  most  valuable,  and  stood 
highest  in  the  list. 

In  this  valuation  no  importance  was  attached  to  the 
form  which  nitrogen  assumed  in  the  various  manures, 
and  just  as  little  to  the  substances  which  were  present 
along  with  the  nitrogenous  compound.  In  this  list  it 
was  quite  immaterial  whether  the  nitrogenous  combina- 
tion was  in  the  form  of  gelatine,  horn,  or  albumen  ;  or 
whether  these  substances  were  or  were  not  accompa- 
nied by  earthy  or  alkaline  phosphates.  Dried  blood, 
claws,  horn  shavings,  woollen  rags,  bones,  rape-cake 
meal,  all  figured  in  one  and  the  same  list. 

As  no  definite  combination  was  understood  by  the 
word  '  nitrogen,'  it  was  impossible  to  prove  that  the 
operation  of  nitrogenous  manures  bore  any  proportion 
to  the  amount  of  nitrogen  which  they  contained. 

The  introduction  and  application  of  Peruvian  guano 
and  nitrate  of  soda  afforded  the  so-called  nitrogen  the- 
ory a  foundation  to  rest  upon ;  no  manure  could  be 
compared  with  guano  for  abundance  of  nitrogen,  while 
it  surpassed  all  others  in  the  rapidity  and  strength  of 
its  action.  The  powerful  effect  produced  by  it  coin- 
cided entirely  with  the  nitrogen  theory  ;  it  correspond- 
ed with  the  high  amount  of  nitrogen  in  the  manure, 
and  chemical  analysis  furnished  satisfactory  conclusions 


280  AMMONIA  AND   NITRIC  ACID. 

with  regard  to  the  rapidity  of  its  action.  The  fact  that 
the  influence  of  guano  in  increasing  the  crops  was  gen- 
erally more  rapid  than  that  of  other  manures  contain- 
ing an  equal  amount  of  nitrogen,  made  it  evident  that 
some  one  of  its  constituents  possessed  a  peculiar  power 
which  was  not  present  in  the  other  manures  ;  and  this 
constituent  was  supposed  to  be  more  conducive  than 
other  nitrogenous  compounds  to  the  growth  of  plants. 

The  discovery  of  this  constituent  presented  no  diffi- 
culty. Chemical  analysis  showed  that  Peruvian  guano 
was  very  rich  in  salts  of  ammonia,  and  that  one-half  of 
its  nitrogen  existed  in  the  form  of  ammonia.  But  am- 
monia was  already  well  known  as  an  element  of  nutri- 
tion for  plants,  and  this  afforded  an  easy  solution  of  the 
rapidity  which  marked  the  operation  of  guano.  Peru- 
vian guano  accordingly  contained  in  a  concentrated 
state  in  the  ammonia  one  of  the  most  important  nutri- 
tive substances  for  plants,  and  this  nutriment  when 
dispersed  in  the  soil  could  be  directly  assimilated  by 
their  roots. 

From  this  time  forward  a  distinction  was  drawn 
between  the  various  kinds  of  nitrogenous  manures,  and 
'  assimilable '  nitrogen  was  discriminated  from  that 
which  was  termed  '  sparingly  assimilable.'  Assimila- 
ble nitrogen  was  understood  to  mean  ammonia  and 
nitric  acid ;  but  the  term  '  hard  of  assimilation '  was 
applied  to  other  nitrogenous  substances,  which  could 
not  be  made  effective  until  their  nitrogen  had  been  con- 
verted into  ammonia. 

The  effect  of  guano  in  raising  large  crops  of  corn 
was  undeniable ;  hence  it  was  according  to  theory  as- 
sumed as  incontestable,  that  its  operation  depended 
upon  the  amount  of  nitrogen  contained  in  it ;  it  was 
further  considered  as  certain,  that  ammonia  was  the 
most  effective  portion  of  the  nitrogen  in  guano.  It  fol- 
lowed, therefore,  as  a  matter  of  course,  that  the  opera- 
tion of  guano  could  be  produced  by  substituting  a  cor- 
responding quantity  of  salts  of  ammonia  ;  and  the  par- 
tisans of  this  theory  believed  that  to  increase  corn  crops 
at  pleasure,  nothing  further  was  necessary  than  to  pro- 


EXPERIMENTS   WITH    SALTS    OF    AMMONIA.  281 


cure  the  requisite  quantity  of  salts  of  ammonia  at  a 
reasonable  price.  Humus  is  the  only  thing  wanting ; 
such  was  the  earlier  opinion.  Now,  it  is  ammonia  is 
the  only  thing  wanting. 

This  conclusion  was  an  immense  step  in  advance  as 
regards  the  views  of  the  importance  of  nitrogen  for 
plants.  Instead  of  attaching  no  determinate  idea  to 
the  word  '  nitrogen,'  the  term  had  now  a  fixed  and 
definite  meaning.  That  which  formerly  was  called 
nitrogen  was  now  termed  (  ammonia,'  an  intelligible, 
ponderable  compound  separable  from  all  other  sub- 
stances which  are  likewise  constituents  of  nitrogenous 
manures,  and  capable  of  being  used  in  experiments,  in 
order  to  test  the  truth  of  the  theory  itself. 

If  the  operation  of  guano  bore  any  proportion  to  its 
nitrogen,  then  a  quantity  of  ammonia  containing  an 
equal  amount  of  nitrogen  must  produce  not  only  the 
same,  but  a  much  greater  effect ;  for  one-half  of  the 
nitrogen  in  guano  exists  in  the  form  which  is  difficult 
of  assimilation,  whereas  the  ammonia  could  be  entirely 
assimilated. 

If  in  any  single  experiment,  the  guano  produced  a 
powerful  effect,  and  the  corresponding  quantity  of  am- 
monia was  inoperative  or  weaker,  this  experiment 
would  be  amply  sufficient  to  confute  the  notion  which 
had  been  attached  to  nitrogen.  For  if  this  notion  was 
correct,  the  ammonia  ought  to  operate  in  all  cases  in 
which  the  guano  operated,  and  exactly  in  the  same 
manner.  The  oldest  experiments  in  this  direction  were 
made  by  Schattenmann  (*  Compt.  rend.'  t.  xvii.). 

He  manured  ten  plots  of  a  large  wheat-field  with 
sal  ammoniac  and  sulphate  of  ammonia ;  an  equally 
large  plot  remained  unmanured.  Of  the  manured 
plots,  one  received  162  kilogrammes  (—  356  Ibs.  Eng.) 
per  acre ;  the  others  received  the  double,  treble,  and 
quadruple  quantity  of  each  of  these  salts. 

The  salts  of  ammonia  (says  Schattenmann,  p.  1130) 
appear  to  exert  a  remarkable  influence  upon  wheat ; 
for,  only  eight  days  after  manuring,  the  plant  assumed 
a  deep  dark-green  colour,  the  sure  sign  of  high  vegeta- 
tive power. 


AMMONIA  AND  NITRIC  ACID. 


The  returns  obtained  by  manuring  with  the  salts  of 
ammonia  were  the  following : — 


Crop. 

Muriate  of  Ammonia  employed. 

Corn. 

Straw. 

Less  Corn,  j  More  Straw. 

kilo.     Ibs. 

kilo.     Ibs. 

kilo.     cwt. 

kilo.    cwt. 

kilo.     cwt. 

kilo.    cwt. 

(1)    1  acre  .    none 
(2)    1    "       .    162=  356 

1182=23 
1138=22 

2867=56 
8217=63 

44=0-8 

348=6-8 

(3)    4    "       .    324=  712 

324=  712  ) 

486=1069 

486=1069  f 

878=17 

3171=62 

304=6-0 

314=6-0 

Average  of  the  four    .    .    .    .  ) 

Sulphate  of  Ammonia  employed. 

kilo. 

kilo. 

(4)    lacre    .    162 

1174=23 

3078=60 

8=0-15 

211=4-0 

(5)    4    "       .324 

324} 

486 

486  f 

903=18 

3248=63 

279=5-3 

381=7-5 

Average  of  the  four    .    .    .    .  ; 

It  is  easy  to  see  that  the  expectations  which  had 
been  founded  upon  the  deep  dark-green  colour  were 
not  realised.  The  salts  of  ammonia  were  so  far  from 
exerting  any  influence  in  augmenting  the  corn-crop, 
that  they  diminished  it  in  every  experiment.  In  the 
crop  of  straw  there  was  a  small  increase. 

In  these  cases  the  salts  of  ammonia  had  not  enlarged 
the  corn  crop,  but  had  produced  the  opposite  effect 
from  guano,  by  which  corn  crops  are  generally  aug- 
mented. 

These  experiments  cannot,  however,  be  regarded  as 
decisive  proofs  against  the  view  of  the  action  of  ammo- 
nia, because  a  comparative  experiment  with  guano  was 
not  made  at  the  same  time  and  place.  It  is  not  impos- 
sible, that  upon  this  particular  field  guano  might  have 
produced  the  same  results.  Some  years  later,  Lawes 
and  Gilbert  published  a  series  of  investigations,  which 
seemed  to  establish  the  operative  power  of  ammonia,  or 
rather  of  salts  of  ammonia.  These  investigations  were 
intended  to  show,  that  the  incombustible  nutritive  sub- 
stances of  wheat  were  not,  of  themselves,  sufficient  to 


EXPEKIMENTS   OF   LAWES   AND   GILBERT.  283 

enhance  the  fertility  of  a  field,  but  that  the  crop  of  corn 
and  straw  stood  rather  in  proportion  to  the  supply  of 
ammonia.  In  fact,  that  increased  crops  could  be  ob- 
tained by  salts  of  ammonia  alone,  inasmuch  as  nitro- 
genous manures  were  peculiarly  adapted -for  the  culti- 
vation of  wheat. 

The  experiments  of  Messrs.  Lawes  and  Gilbert  are 
very  far,  indeed,  from  proving  the  conclusions  which 
they  wish  to  draw ;  they  establish  rather  the  fact  that 
fthese  gentlemen  have  not  the  slightest  notion  of  what 
is  meant  by  argument  or  proof. 

They  did  not  attempt  to  discover  whether  salts  of 
ammonia  alone  could  produce  from  one  portion  of  a 
field  continuous  larger  crops  than  were  yielded  by  an 
unmanured  portion  of  the  same  field. 

Neither  did  they  attempt  to  discover  what  crops 
would  be  yielded  by  an  equal  plot  of  ground  by  ma- 
nuring with  superphosphate  and  potash  salts  during 
a  series  of  years.  But  in  the  first  year  they  supplied 
a  plot  of  ground  for  a  whole  series  of  years  with  the 
constituents  of  corn  and  straw,  phosphoric  acid  and 
silicate  of  potash  (560  Ibs.  of  bone-earth  rendered  solu- 
ble by  sulphuric  acid,  and  220  Ibs.  of  silicate  of  potash), 
and  manured  it,  in  the  following  years,  with  salts  of 
ammonia  only,  and  they  would  have  us  to  believe  that 
the  increased  crops  obtained  under  these  circumstances 
were  due  to  the  operation  of  salts  of  ammonia  alone  ! 

The  imperfect  nature  of  the  experiments  made  by 
Messrs.  Lawes  and  Gilbert  will  appear,  perhaps,  more 
striking,  if  the  question  which  they  pretend  to  solve 
is  stated  in  another  form.  "We  will  assume  that  the 
point  to  be  proved  was,  that  the  high  additional  crops, 
yielded  by  a  wheat  field  manured  with  guano,  were 
due  to  the  operation  of  the  salts  of  ammonia  in  the 
guano,  and  that  its  other  constituents  had  no  share  in 
the  work.  If  the  guano  had  been  lixiviated  with  water, 
and  two  portions  of  a  field  had  been  manured,  the  one 
with  guano,  the  other  with  the  soluble  constituents  of 
an  equal  quantity  of  guano,  only  two  cases  could  occur ; 
the  crop  of  both  plots  would  be  either  equal  or  unequal. 


284  AMMONIA  AND   NITKIO   ACID. 

If  the  crops  were  equal,  it  would  be  manifest  that  the 
insoluble  constituents  of  the  guano  had  no  effect :  if  the 
crop  upon  the  plot  manured  with  guano  was  greater, 
it  would  be  certain  that  the  insoluble  constituents 
(mineral  constituents,  as  Messrs.  Lawes  and  Gilbert 
would  term  them)  had  some  share  in  producing  the 
additional  crop.  The  extent  of  this  share  could  per- 
haps be  determined,  if  a  third  plot  were  manured  with 
the  insoluble  constituents,  i.  e.  with  the  lixiviated  resi- 
due of  an  equal  quantity  of  guano. 

If  an  experimentalist,  in  carrying  out  his  proof,  in- 
stead of  following  this  method,  had,  on  the  contrary, 
lixiviated  the  guano,  and  manured  a  plot  of  ground  in 
\hsfirst  year  with  the  insoluble  constituents  of  the  guano, 
and  in  the  subsequent  years,  with  the  soluble  constitu- 
ents— and  if  he  had  maintained  that  these  soluble  con- 
stituents, in  other  words,  the  salts  of  ammonia  in  the 
guano,  had  alone  produced  the  high  additional  crops, 
and  that  these  bore  a'  proportion  rather  to  the  salts  of 
ammonia  than  to  the  incombustible  constituents  in  the 
guano,  we  should  have  good  grounds  for  concluding 
that  he  had  simply  deceived  himself ;  for,  in  point  of 
fact,  the  field  had  been  manured,  not  with  salts  of  am- 
monia alone,  but  with  all  the  constituents  of  the  guano. 

What  has  here  been  said  in  reference  to  guano, 
which,  as  before  mentioned,  has  the  same  effect  as  a 
mixture  of  superphosphate,  potash,  and  salts  of  am- 
monia, may  be  literally  applied  to  the  experiments  of 
Lawes  and  Gilbert. 

They  manured  their  field,  in  the  first  year,  with  a 
quantity  of  soluble  phosphoric  acid,  lime,  and  potash, 
which  very  nearly  corresponds  with  the  amount  of  these 
substances  in  1750  Ibs  of  guano  ;  and  in  the  subsequent 
years  they  applied  salts  of  ammonia.  The  arable  sur- 
face soil  of  the  field  had,  by  previous  cultivation,  been 
manifestly  exhausted  of  nitrogenous  food ;  and,  under 
these  circumstances,  the  only  wonder  would  have  been 
if  the  nutritive  substances  which  operate  in  guano  had 
been  able,  without  ammonia,  to  yield  as  large  a  crop  as 
wiih>  ammonia. 


EXPERIMENTS    WITH    SALTS   OF   AMMONIA.  285 

These  experiments  are  worth  notice  in  the  history 
of  agriculture,  because  they  show  what  statements  could 
be  laid  before  farmers^  at  a  time  when  ignorance  of  first 
principles  did  not  yet  permit  scientific  criticism. 

With  regard  to  the  influence  of  ammonia  and  salts 
of  ammonia  there  was  instituted  in  the  years  1857  and 
1858,  on  the  part  of  the  General  Committee  of  the  Agri- 
cultural Society  of  Bavaria,  a  series  of  comparative 
experiments  in  the  district  of  Bogenhausen,  as  to  the 
operation  of  guano,  and  various  salts  of  ammonia  con- 
taining an  equal  amount  of  nitrogen,  the  results  of 
which  are  decisive. 

The  experiments  were  conducted  upon  a  field  (a 
loam)  which  had  gone  through  the  usual  rotation,  and 
which,  with  ordinary  farm-yard  manure,  had  borne  rye 
and  then  oats  twice  successively.  Of  eighteen  plots  in 
this  field,  each  1914  square  feet  in  area,  four  were  ma- 
nured with  salts  of  ammonia,  and  one  with  guano,  one 
plot  remained  unmanured. 

As  a  starting  point  for  estimating  the  quantity  of 
manure  to  be  employed,  it  was  assumed  that  400  Ibs. 
of  guano  per  acre  English  (  =  493  Ibs.  avoir.)  corre- 
spond to  the  full  measure  of  farm-yard  manure  usually 
applied.  According  to  this  proportion,  20  Ibs  (  =  24f 
Ibs.  avoir.)  of  guano  were  reckoned  for  the  area  in 
question. 

The  samples  of  good  Peruvian  guano  selected  were 
previously  analysed,  and  in  100  parts  a  quantity  of 
nitrogen  was  found  corresponding  to  15*39  of  ammonia. 
As  a  general  rule,  only  one-half  of  the  nitrogen  in 
guano  is  present  as  ammonia ;  the  other  half  appears 
as  uric  acid,  guanine,  &c.,  of  the  operation  of  which 
upon  the  growth  of  plants  little  or  nothing,  as  we  have 
before  observed,  is  known.  But  it  was  assumed  that 
the  nitrogen  in  these  other  substances  was  just  as  oper- 
ative as  that  in  the  ammonia,  and  the  quantum  of  the 
various  salts  of  ammonia  (which  were  likewise  analysed 
previously  to  ascertain  exactly  their  amount  of  ammonia) 
was  reckoned  in  accordance  with  this  assumption.  Ac- 
cordingly, for  the  above  20  Ibs.  of  guano,  1719  grammes 


286  AMMONIA   AND   NITRIC   ACID. 

(  =  3 '75  Ibs.)  of  ammonia  were  computed  as  the  equiva- 
lent ;  and  each  of  the  other  four  plots  received  exactly 
the  same  quantity  of  ammonia,  in  the  salt  of  ammonia 
employed  for  manure. 

It  is  clear  that  if  an  increased  crop  was  obtained  by 
means  of  the  guano,  and  if  this  was  due  to  the  amount 
of  its  nitrogen,  then  each  of  the  other  four  plots,  having 
received  the  same  quantity  of  nitrogen,  must  necessarily 
be  affected  exactly  in  the  same  manner  as  if  they,  also, 
had  been  manured  with  20  Ibs.  of  the  same  guano.  The 
results  were  as  follow : — 

Comparative  experiments  at  Bogenhausen  with  guano  and  salts 
of  ammonia  containing  equal  quantities  of  nitrogen. 

HARVEST,  1857. — BARLEY. 

Grain.  Straw, 

grammes.  Ibs.  grammes.        grammes. 

Manured  with  5880=13    carbonate  of  ammonia. .  6335  16205 

"             4200=  9    nitrate  8470  16730 

"             6720=14|  phosphate           "  7280  17920 

6720=14|  sulphate             "  6912  18287 

"         20  lbs.  =  24f  av.  guano 17200  33320 

Unmanured     6825  18375 

Although  each  of  the  four  plots  had  received  the 
same  quantity  of  nitrogen,  still  their  respective  crops 
did  not  correspond ;  on  the  whole,  the  crop  from  the 
plots  manured  with  salts  of  ammonia,  corn  and  straw 
together,  was  in  each  case  very  little  higher  than  that 
of  the  unmanured  plot ;  while  the  plot  manured  with 
guano  yielded,  for  the  same  quantity  of  nitrogen,  2-J- 
times  more  corn,  and  80  per  cent,  more  straw,  than  the 
average  crop  of  the  plots  manured  with  salts  of  am- 
monia. 

In  the  subsequent  year,  this  experiment  was  re- 
peated in  a  similar  manner  in  the  same  district  with 
winter  wheat.  The  field  chosen,  and  to  which  six 
years  previously  farm-yard  manure  had  been  applied, 
had  borne  winter  rye,  then  clover,  and  then  oats,  for 
three  years.  The  oat  stubble  was  broken  up  and  then 
twice  ploughed  :  on  the  12th  September,  1857,  the  seed 


BOGENHAtTSEN   EXPERIMENTS.  287 

was  sown  and  harrowed  in,  on  one  day  :  immediately 
after  the  sowing  there  was  a  moderate  thunder  shower. 
The  field  was  divided  into  seventeen  lots,  each  of 
1900  square  feet,  which  were  separated  from  each  other 
by  furrows  ;  each  was  separately  sown  and  harrowed. 
The  quantity  of  guano  used  was  18-8  Ibs.  (  =  23  -3  Ibs. 
avoir.),  and  the  weight  of  the  salts  of  ammonia  employed 
was  calculated  from  the  amount  of  nitrogen  in  the  guano, 
so  that,  as  in  the  previous  experiment,  each  plot  received 
an  exactly  equal  amount  of  nitrogen.  The  results  were 
the  following  :  — 

Experiment  in  Bogenhausen. 

RESULT  OP  HARVEST,  1858.  —  WINTER-WHEAT. 

Corn.  Straw. 

grammes.      grammes. 

Manured  with  guano,  yielded     .................     32986  791  60 

19600  41440 

21520  38940 

25040  •       57860 

27090  65100  - 


sulphate  of  ammonia  (11 '8  Ibs.  Bav. 
phosphate         "         (11*9 
carbonate         "         (10-6 
nitrate  "        (  7'1 


TJnmanured  ...................  ."  ..........  '...     18100  32986 

These  experiments  show  in  the  clearest  manner  that 
it  is  an  error  to  refer  the  effect  of  a  powerful  nitroge- 
nous manure  chiefly  to  the  nitrogen  which  it  contains. 
]STo  doubt  it  has  a  share  in  the  operation  of  these  ma- 
nures, but  their  energy  is  not  in  proportion  to  the 
amount  of  nitrogen  in  them. 

If  ammonia  or  salts  of  ammonia  increase  the  prod- 
uce of  a  field,  their  effect  depends  upon  the  nature  of 
the  soil.  What  we  mean  here  by  the  nature  of  the  soil 
is  understood  by  every  one  ;  the  ammonia  can  engender 
in  the  soil  no  potash,  no  phosphoric  acid,  no  silicic  acid, 
no  lime  ;  and  if  these  substances,  which  are  indispensa- 
ble for  the  developement  of  the  wheat  plant,  are  not 
found  in  the  soil,  the  ammonia  cannot  produce  any 
effect  whatever.  If,  then,  in  Schattenmann's  experi- 
ments, and  those  at  Bogenhausen,  there  were  no  results 
from  the  salts  of  ammonia,  this  did  not  arise  from  the 
fact  of  these  salts  being  in  themselves  ineffective  ;  but 
they  were  inactive,  because  the  conditions  of  their  ac- 


288  AMMONIA  AND  NITRIC  ACID. 

tivity  weve  wanting.  Lawes  and  Gilbert  supplied  these 
conditions  to  their  field,  and  hence  ensured  activity  to 
the  ammoniacal  salts  they  used. 

The  results  obtained  by  Kuhlmann  respecting  the 
effect  of  salts  of  ammonia  upon  meadows  are  precisely 
similar.  He  manured  a  piece  of  meadow  land  with 
sulphate  of  ammonia,  and  obtained  a  crop  of  hay  larger 
than  the  yield  of  the  unmanured  plot,  because  a  certain 
quantity  of  phosphoric  acid,  potash,  &c.  was  rendered 
active,  which  without  the  cooperation  of  salts  of  am- 
monia, would  not  have  been  the  case.  On  adding 
phosphate  of  lime  to  the  salts  of  ammonia,  the  activity 
of  the  latter  was  enhanced  in  an  extraordinary  degree  ; 
he  obtained, — 

Return  of  hay,  per  hectare,  1844. 

Excess  above  the 
unmanured  plot, 
kilo.  kilo.  kilo. 

(1)  By  manuring  with  250  sulphate  of  ammonia  . .     5564         1744 

(2)  "  333  sal  ammoniac,  with  phos- 

phate of  lime 9906         6086 

(3)  Unmanured  plot    3820 

Thus,  by  sulphate  of  ammonia  alone,  Kuhlmann  ob- 
tained rather  more  than  half  as  much  hay  again  as  the 
yield  of  the  unmanured  plot ;  and  by  adding  phosphate 
of  lime  he  gained  almost  three  times  as  much. 

Those  who  maintained  the  theory  of  the  special  im- 
portance to  agriculture  of  nitrogen  in  manure,  formed 
a  similar  notion  about  the  cause  of  fertility  in  land. 

If,  in  fact,  the  efficacy  of  any  manure  depended  on 
the  enrichment  of  the  soil  with  nitrogen,  exhaustion 
could  be  explained  only  by  the  diminution  of  the  store 
of  nitrogen ;  and  the  manure  would  restore  fertility 
when  the  nitrogen  which  had  been  removed  in  the  har- 
vest was  again  supplied  by  it  to  the  field.  Accordingly, 
the  unequal  fertility  of  land  must  be  due  to  the  unequal 
amounts  of  nitrogen  contained  in  it ;  and  it  would  fol- 
low that  the  soil  richer  in  nitrogen  must  be  more  fruit- 
ful than  one  which  contained  less  of  this  element. 

This  theory,  too,  came  to  a  pitiful  end ;  since  that 


FERTILITY   OF  LAND   NOT   DUE   TO   ITS   NITROGEN.      289 

which  was  not  true  for  manures  could  not  possibly  hold 
good  for  land. 

Every  one  who  is  acquainted  with  chemical  analysis 
knows  that  among  the  constituents  of  the  soil  none  can 
be  approximately  determined  with  greater  accuracy  than 
nitrogen.  In  an  exhausted  soil  at  Weihenstephan  and 
Bogenhausen,  nitrogen  was  determined  by  the  usual 
method,  and  calculated  to  a  depth  of  10  inches. 

The  field  contained,  per  hectare, 

Bogenhausen.       Weihenstephan. 
kilogr.  kilogr. 

Nitrogen  5145  5801 

On  both  fields  summer  barley  was  cultivated  in 
1857,  and  the  following  returns  were  obtained,  per  hec- 
tare : — 

Bogenhausen.        Weihenstephan. 
kilogr.  kilogr. 

Corn 413  1604 

Straw  1115         2580 

1528      .   4184 

Thus,  the  field  at  "Weihenstephan,  containing  about 
the  same  amount  of  nitrogen,  yielded  almost  four  times 
as  much  corn,  and  more  than  twice  as  much  straw,  as 
the  field  at  Bogenhausen. 

In  1858,  these  experiments  were  repeated  at  Weihen- 
stephan with  winter  wheat,  and  at  Schleissheim  with 
winter  rye  ;  the  result  was  : — 

Nitrogen  contained  to  the  depth  of  10  inches,  per  hectare, 

Schleissheim.  Weihenstephan. 

kilogr.  kilogr. 

2787  5801 

Crop. 

Corn 115  1699 

Straw 282-6  3030 

397-6  4729 

The  amount  of  nitrogen  in  the  field  at  Schleissheim, 
as  compared  with  that  at  Weihenstephan,  bears  the 

13 


290  AMMONIA   AND   NITRIC   ACID. 

proportion  of  1 :  2 ;  whereas  the  crops  are  in  the  pro- 
portion of  1 :  14.  These  facts  are  fatal  to  the  opinion 
that  there  exists  any  connection  between  the  amount 
of  nitrogen  in  a  soil,  and  its  powers  of  production  ;  and 
in  truth  no  one  now  entertains  this  belief.  For  since 
Kroker  in  1846  determined  the  nitrogen  in  22  kinds  of 
soil  from  various  districts,  and  discovered  that  even  an 
unfruitful  sand  contained  more  than  a  hundred  times, 
while  in  arable  soils  to  a  depth  of  10  inches  there  were 
present  from  500  to  1000  times,  more  nitrogen  than  is 
necessary  for  a  good  crop,  similar  investigations  have 
been  made  in  all  countries,  and  Broker's  results  have 
been  confirmed. 

Since  that  period  the  fact  has  been  generally  ad- 
mitted, that  the  great  majority  of  cultivated  soils  are 
far  richer  in  nitrogen  than  in  phosphoric  acid ;  and 
that  the  relative  proportion  of  nitrogen  present,  which 
had  been  adopted  as  the  standard  for  calculating  the 
value  of  manure,  was  quite  inapplicable  for  estimating 
the  productive  power  of  land. 

Hence,  between  the  chemical  analysis  of  manures, 
and  that  of  the  soil,  there  arose  an  irreconcilable  con- 
tradiction. In  the  chemical  laboratory  the  effective 
value  of  a  manure  could  be  accurately  determined  ac- 
cording to  the  per  centage  of  its  nitrogen  ;  but  when 
the  farmer  had  incorporated  his  manure  with  the  soil, 
the  determination  of  the  per  centage  of  nitrogen  in  the 
ground  was  no  longer  of  any  use  in  estimating  its  pro- 
ductive power. 

This  strange  circumstance  might  well  have  excited 
suspicion  against  the  theory  of  the  preponderating  in- 
fluence of  nitrogen,  for  which,  as  already  observed,  there 
is  not  the  slightest  evidence  in  point  of  fact.  But  in- 
stead of  this,  the  advocates  of  the  theory  maintained  it 
steadfastly,  and  endeavoured  to  explain  the  behaviour 
of  the  soil  upon  new  and  still  more  extraordinary 
grounds.  It  had  been  observed  that  a  very  small  frac- 
tion of  the  quantity  of  nitrogen  present  in  the  soil,  in 
the  form  of  guano,  farm-yard  manure,  or  nitrate  of  soda, 
materially  increased  the*  crops ;  whereas,  the  effect  of 


DIFFERENT  FORMS   OF   NITROGEN   IN   THE   SOIL.        291 

other  manures,  which  contained  nitrogen  not  in  the 
form  of  ammonia  or  nitric  acid,  was  very  unequal  in 
respect  of  time,  and,  in  the  case  of  horn  shavings  or 
woollen  rags,  was  extremely  slow.  This  led  to  the 
assumptioiAhat  the  nature  of  nitrogen  was  as  variable 
in  the  arable  soil  as  in  manures  ;  one  portion  was  sup- 
posed to  be  in  the  form  of  ammonia  or  nitric  acid,  and 
this  was,  properly  speaking,  the  effective  part;  another 
portion,  on  the  contrary,  existed  in  some  peculiar  form 
which  could  not  exactly  be  defined,  and  was  quite  in- 
effective. 

Hence  the  productive  power  of  a  soil  was,  according 
to  this  view,  not  in  proportion  to  the  entire  quantity 
of  nitrogen  in  it,  but  could  only  be  measured  by  the 
nitric  acid  and  ammonia  which  it  contained.  As  the 
advocates  of  the  theory  about  the  effective  operation 
of  nitrogen  had  been  accustomed  to  shirk  proving  the 
truth  of  their  doctrine,  as  a  matter  of  course  they^  did 
not  trouble  themselves  about  adducing  any  positive 
facts  in  support  of  this  extension  of  it.  They  believed 
that  they  could  establish  their  point  in  the  following 
way. 

When  a  crop  contained  in  corn  and  straw  as  much 
nitrogen  as  was  equivalent  to  six,  four,  three,  or  two 
per  cent,  of  the  whole  quantity  of  nitrogen  in  the  soil, 
the  reason  was  that  there  were  present  in  the  field  six, 
four,  three,  or  two  per  cent,  of  active  nitrogen,  while 
the  remaining  94,  96,  97,  or  98  per  cent,  were  inoper- 
ative nitrogen. 

The  cause  of  the  effect  (the  amount  of  active  nitro- 
gen in  the  soil)  was  consequently  inferred  from  the 
effect  (the  amount  of  nitrogen  in  the  crops).  If  more 
of  the  whole  quantity  of  nitrogen  was  in  an  active  form, 
then  higher  crops  would  follow ;  if  the  crops  were  lower, 
the  reason  was  that  there  was  a  deficiency  of  active 
nitrogen.  If  in  guano  or  farm-yard  manure  additional 
active  nitrogen  was  supplied,  the  crops'  would  be  in- 
creased. 

By  taking  a  new  standard  for  estimating  the  pro- 
ductive power  of  the  soil,  the  former  one  for  the  valu- 


292  AMMONIA   AND   NITKIC   ACID. 

ation  of  manure  was  virtually  abandoned.  For  when 
efficiency  was  allowed  only  to  nitric  acid  and  ammonia 
in  the  soil,  and  denied  to  all  other  nitrogenous  combi- 
nations, it  was  evidently  unwarrantable  to  place  those 
nitrogenous  compounds  in  manures,  which  were  neither 
ammonia  nor  nitric  acid,  in  the  same  class  with  these 
two  elements  of  food. 

But  in  the  classified  estimate  of  manures,  a  high 
place  was  given  to  dried  blood,  horn  shavings,  gelatine, 
and  the  nitrogenous  constituents  of  rape-cake,  all  sub- 
stances  which  contain  neither  nitric  acid  nor  ammonia. 
The  favourable  effect  of  these  manures  was,  in  the  ma- 
jority of  cases,  undoubted,  but  still  not  determinable 
by  analysis.  Of  two  fields,  the  one  manured  with  rape- 
cake,  the  other  not,  the  former  yields  a  larger  corn  or 
turnip  crop  than  the  latter,  but  it  is  not  possible  to 
show  that  there  was  more  ammonia  in  the  one  case 
than  in  the  other.  True,  it  was  assumed  that  the  nitro- 
genous compounds  of  these  manures,  the  albumen  of 
the  blood,  the  rape-cake,  or  the  gelatine,  was  gradually 
converted  into  ammonia,  and  so  became  operative  ;  but 
it  was  taken  for  granted  as  a  matter  of  course,  that  the 
so-called  inoperative  nitrogenous  compounds  present  in 
the  soil  do  not  possess  the  power  of  yielding  ammonia, 
or  of  being  oxydised  into  nitric  acid. 

It  was  well  known,  indeed,  that  if  one  of  two  fields 
contained  more  lime  than  the  other,  the  one  richer  in 
lime,  often  did  not  on  that  account  produce  more  clover. 
Yet  no  one  thought  of  assuming  that  the  lime  in  the 
richer  field  existed  in  a  two-fold  condition,  operative 
and  inoperative,  or  that  the  active  portion  of  the  lime 
had  caused  the  difference  in  the  clover  crops. 

It  was  also  well  known  that  if  two  fields  be  manured 
with  the  same  bone-earth,  the  one  often  gave  a  higher 
crop  than  the  other,  and  yet  no  one  thought  of  assum- 
ing that  in  the  second  field  the  inefficiency  of  the  bone- 
earth  was  due  to  the  fact  that  it  had  passed  into  a  state 
of  inactivity. 

It  was  further  known,  that  the  excess  of  no  individ- 
ual nutritive  substance  exercised  any  influence  upon 


NITROGEN  IS  NOT  UNDER  TWO   FORMS   IN   SOILS.      293 

the  produce  of  a  field ;  but  it  was  assumed  that  the 
case  must  be  different  with  nitrogen.  A  surplus  of  that 
element,  it  was  surmised,  must  act,  and  if  it  did  not, 
the  cause  was  not  ascribed  to  the  field,  but  to  the  na- 
ture and  condition  of  the  nitrogenous  compounds. 

From  this  we  see  that  the  notion  of  nitrogen  exert- 
ing the  principal  influence  in  agriculture  led  to  unex- 
ampled confusion  of  thought  and  to  the  most  baseless 
and  absurd  suppositions.  None  of  the  advocates  of  this 
theory  gave  themselves  the  slightest  trouble  to  extract 
from  the  ground  one  of  the  nitrogenous  compounds, 
which  were  deemed  inoperative,  so  as  to  study  its  na- 
ture ;  but  properties  were  ascribed  to  them,  of  which 
nothing  could  be  known,  because  the  things  themselves 
were  not  known. 

As  the  advocates  of  this  theory  can  say  nothing 
about  the  nature  of  the  nitrogenous  compounds  present 
in  the  ground,  they  want  to  make  us  believe  that  noth- 
ing at  all  is  known  about  them.  But  no  one,  who  has 
an  acquaintance  with  chemistry,  has  the  smallest  doubt 
or  uncertainty  respecting  the  origin  of  nitrogen  in  the 
arable  soil.  It  is  derived  either  from  the  air,  whence 
it  is  conveyed  to  the  earth  in  rain  or  dew ;  or  from  or- 
ganic substances  accuumulated  from  a  series  of  gener- 
ations of  dead  and  decayed  plants,  or  else  from  animal 
remains  contained  in  the  earth,  or  incorporated  with  it 
by  man  in  the  form  of  excrements.  Animal  and  human 
excrements,  bodies  of  animals  in  the  earth,  corpses  in 
their  coffins,  all  vanish,  with  the  exception  of  their  in- 
combustible matters,  after  a  series  of  years ;  the  nitro- 
gen of  their  constituents  is  converted  into  gaseous  am- 
monia, and  is  distributed  in  the  surrounding  soil.  The 
remains  of  extinct  animal  life  which  are  embedded,  to 
an  enormous  extent,  in  sedimentary  strata,  or  which 
of  themselves  constitute  whole  masses  of  rock,  attest 
the  extraordinary  distribution  of  organic  life  in  the 
former  ages  of  the  earth  ;  and  it  is  the  nitrogenous  con- 
stituents of  these  animal  bodies,  passing  over  into  am- 
monia and  nitric  acid,  which  still  play  an  important 
part  in  the  economy  of  the  vegetable  and  animal  world. 


294:  AMMONIA  AND   NITKIC   ACID. 

If  the  smallest  doubt  could  exist  on  this  question, 
it  is  completely  removed  by  the  investigations  of  Schmid 
and  Pierre  ('  Compt.  rend.'  t.  xlix.  pp.  711-715). 

Schmid  examined  (see  Peters.  4  Acad.  Bull.'  viii. 
161)  several  specimens  of  Kussian  black-earth  (tscherno- 
sem)  from  the  Government  of  Orel,  and  among  them 
three  from  the  same  field,  marked  by  him  as  '  virgin 
soil,'  of  which  we  may  assume  that  it  had  never  been 
subject  to  agricultural  operations  ;  the  amount  of  nitro- 
gen in  this  soil  amounted  to — 

Amount  of  nitrogen  in  the  tscherno-sem. 

Under  the  turf 0*99  per  qent.  nitrogen 

4  werschoks  (=  7  inches)  deeper. .     0-45         "  " 

Above  the  subsoil 0'33         " 

If  we  assume  a  cubic  decimetre  (  —  61  cubic  in.)  of 
this  earth  to  weigh  1100  grammes  (  —  2'4  Ibs.),  then, 
calculating  for  the  area  of  a  hectare  (  —  2-J  acres),  the 
ground  would  contain — 

kilo.      cwt. 
1  decimetre  (=  4  inches)  deep    , . . .  10890  =  213  nitrogen 

1         "  "         deeper 4950=  97         " 

1         "  "  "  3630  =  71         " 


30  centimetres  (=11-7  inches)  deep. .  19470  =  381         " 

In  examining  a  soil  in  the  neighbourhood  of  Caen, 
Pierre  found  in  it  19620  kilogrammes  (  =  385  cwt.)  of 
nitrogen  distributed,  in  the  following  manner,  through 
a  hectare  to  the  depth  of  one  metre  (  —  3*3  feet.) 

centimetres,    inches.  kilogr.  cwt. 

In  the  first    layer  of         25  =10          deep,  the  soil  contained  8360  =  164 

"     second  "        25—50  =  10—20     "  4959  =    97 

"      third      "         50—75  =  20—30     "  3479  =    68 

"      fourth   "      75—100  =  30—40     "  "  2816=    55 


19614=384 


Thus,  according  to  both  investigations,  the  uppermost 
layers,  or  the  proper  arable  soil  (about  10  inches  deep), 
were  the  richest  in  nitrogen,  while  in  the  lower  layers 
the  amount  decreased. 


NITROGEN   IN   THE   DIFFERENT   LAYERS   OF   SOILS.      295 

Such  a  condition  undeniably  proves  the  origin  of 
nitrogen  in  the  arable  soil. 

If  the  upper  layers  which  are  constantly  deprived 
of  nitrogen  by  cultivation,  contain  more  of  this  element 
than  the  lower,  it  necessarily  follows  that  the  nitrogen 
must  have  come  from  without.  The  analysis  of  the 
most  various  kinds  of  soil  in  many  different  lands  and 
districts  shows  that  there  is  scarcely  a  single  fruitful 
wheat  soil  which  does  not  contain  at  least  5000  to  6000 
kilogrammes  (  —  98  to  118  cwt.)  of  nitrogen  per  hec- 
tare (  =  2-J  acres)  to  the  depth  of  25  centimetres  (;=  10 
inches) ;  and  the  simplest  comparison  of  the  quantity 
of  nitrogen  in  the  soil,  with  that  which  is  removed  in 
the  crops,  proves  that  the  latter  amounts  to  a  very  small 
fraction,  and  that  the  land  is  exhausted  of  all  other 
nutritive  substances  sooner  than  of  nitrogen. 

The  experiments  of  Mayer  (c  Ergeb.  landw.  u.  agric. 
Yersuche.'  Miinchen.  Iter  Heft,  s.  129)  show  that  the 
behaviour  of  arable  soil  with  respect  to  alkalies  in 
watery  solution  affords  no  conclusion  as  to  the  nature 
of  the  nitrogenous  compounds  therein  contained.  It 
had  been  assumed,  that  all  nitrogen  in  the  earth  in  the 
form  of  ammonia  could  be  separated  by  distillation 
with  caustic  alkalies,  and  that  the  portion  that  was  not 
thus  separated  did  not  exist  as  such.  Mayer  proved 
the  incorrectness  of  this  assumption ;  he  first  discovered, 
that  many  earths  rich  in  humous  constituents  when 
boiled  for  four  hours  (which  may  be  considered  equiva- 
lent to  lixiviation  for  four  hours  with  boiling  water) 
still  retained  a  very  considerable  quantity  of  ammonia. 
The  earths  employed  in  these  experiments  were  (1)  earth 
from  the  hollow  trunk  of  a  tree,  (2)  garden  soil  rich  in 
organic  matters,  from  the  Botanic  Garden,  (3)  strong 
clay  soil  from  Bogenhausen. 

Ammonia. 

One  million  milligrammes  (  =  2-2  Ibs.)  retained  at  the  temperature  of 

boiling  water : 

milligr.    grs.  milligr.   grs.  miliigr.   grs. 

(1)  Tree  soil,  7308  =  112  (2)  Garden  soil,  4538  =  70  (3)  Clay,  1576  =  24 

If  an  arable  soil  after  saturation  with  ammonia,  by 


296  AMMONIA   AND   NITRIC   ACID. 

being  placed  either  in  a  weak  solution  of  pure  ammonia, 
or  in  a  confined  space  with  amnioiiiacal  gas,  or  over 
carbonate  of  ammonia,  is  then  dried  and  exposed  in 
thin  layers  in  this  dry  state  to  the  air  for  fourteen  days, 
all  the  ammonia  not  intimately  combined  in  the  soil  is 
evolved,  and  the  same  result  may  be  produced  by  con- 
stant washing  with  cold  water.  Now  if  soils  thus  satu- 
rated, the  ammonia  of  which  has  been  accurately  ascer- 
tained, are  exposed  to  distillation  with  soda  lye,  it  is 
found  that  a  considerable  portion  of  the  absorbed  am- 
monia is  not  separable  in  this  way.  In  the  following 
table,  A  expresses  the  quantity  of  ammonia  respectively 
absorbed  by  various  soils  at  the  ordinary  temperature 
of  the  air  ;  B,  the  quantity  of  ammonia  retained  by  the 
same  soils  after  twelve  to  fifteen  hours'  action  of  soda 
lye  in  a  water  bath. 

One  million  milligrammes  ( =  2'2  Ibs.)  of  soil  from 

Havannah.      Schleissheim.    Bogenhausen.  Clay  soil. 

milligr    grs.         milligr.   grs.         milligr.  grs  milligr.  grs. 

A  Ammonia...  5520  —  85    3900  =  60    3240  =  50  2600  =  40 

B    "    ...   020-14    970=15     990=15  470=  7 

Under  these  circumstances,  it  appears  that  the 
power  of  retaining  a  certain  portion  of  the  absorbed 
ammonia  is  very  unequal ;  the  Havannah  earth  (a  poor 
lime  soil)  retains  a  sixth  of  the  absorbed  ammonia,  the 
soil  at  Schleissheim  the  fourth,  that  at  Bogenhausen 
almost  a  third.* 

*  We  need  not  be  surprised  at  this  peculiar  comportment,  for  it  merely 
proves  that  part  of  the  ammonia  in  the  earth  is  contained  in  an  entirely 
different  form  from  that  of  a  salt.  The  salts  of  ammonia  are  combinations 
of  ammonium,  which  can  be  easily  decomposed  by  alkalies,  alkaline  earths, 
and  metallic  oxides,  the  alkali  taking  the  place  of  oxide  of  ammonium,  or 
the  ammonium  being  displaced  by  some  other  metal.  But  we  have  no 
reason  to  believe,  that  the  ammonia,  which  by  physical  attraction  is  fixed 
in  the  porous  arable  soil,  yields  its  place  to  another  body,  and  is  separable 
by  it,  if  the  latter  has  not  a  stronger  attraction  for  the  soil. 

Carbonate  of  lime,  in  the  cold,  produces  scarcely  any  effect  upon  sul- 
phate of  ammonia ;  but  in  an  arable  soil,  which  contains  carbonate  of  lime, 
the  salt  of  ammonia  is  completely  decomposed  :  lime  takes  the  place  of  the 
ammonia,  the  latter  however  does  not  become  free,  but  enters  into  some 
other  combination,  upon  which  lime  has  no  effect. 


AMMONIA   RETAINED   FIRMLY   BY    SOILS.  297 

This  explains  the  reason  why  an  arable  soil  saturated 
with  ammonia  gives  back  only  a  portion  after  being 
heated  with  soda  lye  for  several  hours ;  and  it  is  rather, 
perhaps,  the  lengthened  operation  of  water  at  a  high 
temperature,  than  the  chemical  attraction  of  the  soda, 
that  gradually  separates,  in  the  form  of  gas,  the  am- 
monia fixed  by  the  soil.  In  this  operation  there  is  no 
perceptible  limit,  where  the  evolution  of  ammonia 
ceases ;  for  even  after  twenty-five  hours  of  continuous 
heating  in  a  water-bath,  the  fluid  which  passes  off  has 
still  an  alkaline  reaction. 

The  above  arable  soils  in  their  natural  condition 
comport  themselves  with  a  boiling  solution  of  soda 
precisely  as  if  they  were  partially  saturated  with  am- 
monia. In  the  following  table,  A  expresses  the  total 
quantity  of  nitrogen  in  the  form  of  ammonia,  which  is 
obtained  from  various  soils  at  a  red  heat  with  soda 
lime ;  B,  the  quantity  of  ammonia  which  is  separable 
from  them  after  twelve  to  twenty-five  hours'  heating 
with  a  solution  of  soda. 

One  million  milligrammes  of  earth  =  ( 1  kilo.  —  2'2  Ibs.)  from 

Havannah.         Schleissheim.     Bogenhausen.          Clay  soil, 
milligr.    grs.          milligr.    grs.        milligr.    grs.          milligr.    grs: 

A  2640=40-6         4880  =  75.0         4060  =  62-5         2850  =  44  "0 

B 510=7-8         1270  =  19-5  850  =  12  830  =  12-7 

These  numbers  lead  to  some  interesting  consider- 
ations ;  they  show,  among  other  things,  that  the  third, 
fourth,  or  fifth  part  of  all  the  nitrogen  contained  in  the 
soil  is  separable  in  the  form  of  ammonia ;  and  that  after 
twenty-five  hours'  distillation  with  a  solution  of  soda, 
the  fluid  which  passes  off  has  still  an  alkaline  reaction. 

As  a  soil  saturated  with  ammonia  retains,  after  five 
or  six  hours'  heating  with  a  solution  of  soda,  a  third, 
a  fourth,  or  a  sixth  of  the  ammonia  absorbed  by  it,  and 
we  cannot  assert  that  the  retained  portion  has  changed 
its  nature,  and  is  no  longer  ammonia ;  so  from  the  com- 
portment of  the  earth  in  its  natural  condition,  and  under 
the  same  circumstances,  we  cannot  conclude  that  the 
nitrogen  which  by  distillation  cannot  be  obtained  in 

13* 


298  AMMONIA  AND   NITKIC  ACID. 

the  form  of  ammonia,  does  not,  therefore,  exist  as  such 
in  the  earth. 

Even  if  the  experiments  above  described  do  not 
afford  any  proof  that  all  the  nitrogen  in  the  ground  is 
in  the  form  of  ammonia  (a  portion,  besides,  is  in  most 
cases  present  as  nitric  acid),  there  is,  on  the  other  hand, 
no  proof  furnished  to  the  contrary. 

Strictly  speaking,  the  discussion  of  the  point  in 
question  does  not  depend  on  this  proof  ;  for  it  is  suffi- 
cient to  show  here,  that  the  comportment  of  the  soil 
i  with  respect  to  the  amount  of  nitrogen  in  it  is  exactly 
the  same  as  that  of  farm-yard  manure.  Only  a  small 
portion  of  the  nitrogen  in  farm-yard  manure,  is  sepa- 
rable by  distillation  with  alkalies  ;  the  much  larger  por- 
tion being  obtained  only  by  complete  decomposition  of 
the  substances. 

According  to  Yoelker's  analysis,  800  cwt.  of  fresh 
farm-yard  manure  contained  — 

1854,  November.     1855,  April. 

Ibs.  Ibs. 

Nitrogen  ....................................  514  712 

Ammonia  "        *     ............  97-6  H-t 


If  we  compare  with  this  the  amount  of  separable 
ammonia  and  the  total  nitrogen  in  the  soil  at  Schleiss- 
heim  and  Bogenhausen,  we  have  — 

Schleissheim.  Bogenhausen. 

Ibs.  Ibs. 

800  cwt.  of  arable  soil  contain  nitrogen  ......  321'6  267'2 

Present  as  separable  ammonia  ..................  101'6  68'0 

It  is  manifest,  that  when  two  soils,  not  particularly 
rich  in  nitrogen,  contain  just  as  much  ammonia  as  an 
equal  weight  of  farm-yard  manure,  if  we  ascribe  the 
effect  of  the  latter  merely  to  the  amount  of  ammonia 
which  it  contains,  then  the  unfruitfulness  of  the  field 
at  Schleissheim  is  entirely  inexplicable. 

We  assume  that  the  entire  quantity  of  nitrogen  in 
farm-yard  manure  has  a  definite  share  in  its  operation  ; 
and  as  the  nitrogenous  matters  in  the  arable  soil  are 
originally  identical  with  the  substances  which  form  the 


CHOPS   NOT   IN   PROPORTION    TO    NITROGEN    IN    SOIL.       299 

constituents  of  manures,  it  is  impossible  to  ascribe  to 
the  one  an  effect  which  does  not  equally  apply  to  the 
other. 

There  can  be  no  doubt  that  the  nitrogenous  com- 
pounds in  the  ground  often  exert  no  influence  in  increas- 
ing the  crops,  while  those  in  the  manures  undoubtedly 
produce  a  favourable  effect.  Hence  the  operation  of 
the  nitrogenous  compounds  in  the  manure  must  have 
depended  upon  causes  which  the  ground  did  not  sup- 
ply ;  and  it  is  clear  that  the  same  efficacy  can  be  given 
to  the  nitrogenous  compounds  in  the  soil,  if  the  farmer 
will  take  care  to  bring  into  play  the  causes  which  pro- 
duced the  favourable  operation  in  the  manures. 

If  we  consider,  for  example,  the  crops  yielded  (see 
pp.  148  and  151)  by  the  two  fields  at  Schleissheim  in 
an  unmanured  condition,  and  compare  them  with  the 
quantity  of  nitrogen  in  the  soil,  the  result  is — 

Nitrogen,  per  hectare  ( =  2£  acres). 

To  the  depth  of  10  inches.  Produce. 

Corn.  Straw. 

In  Field  1  (p.  151),  1858     ...     2787  kilo.         115  kilo.         282  kilo. 
In  Field  2  (p.  148),  1857     ...     4752     "  644    "  1656     " 

Those  who  maintain  that  the  crops  depend  upon 
the  nitrogen  in  the  soil,  would  judge  the  results  of  these 
two  experiments  somewhat  in  the  following  way  : — 

The  amount  of  nitrogen  in  both  fields  is  as     100  :  160 

The  corn  crops  as  ; 100  :  560 

If  the  crops  are  in  proportion  to  the  quantity  of 
effective  nitrogen  in  the  soil,  it  follows  that  the  soil  of 
Field  2  contained,  not  only  altogether,  but  even  propor- 
tionately, more  than  Field  1.  If  the  corn  crop  in  Field 
1  =  115  kilogrammes  corresponded  to  the  fraction  of 
effective  nitrogen  in  the  whole  amount  of  nitrogen  = 
2787  kilogrammes,  then  Field  2  ought  to  have  yielded 
257  kilogrammes  of  corn,  supposing  that  the  relative 
proportion  of  active  and  inactive  nitrogen  were  the 
same  as  in  Field  1  (for  2787  kilogrammes,  nitrogen  : 
115  kilogrammes,  corn  =  4752  kilogrammes,  nitrogen: 


300  AMMONIA  AND  NITRIC   ACID. 

257  kilogrammes,  corn).  But,  in  fact,  Field  2  yielded 
two  and  a  half  times  as  much  corn  ;  and  therefore  the 
amount  of  active  nitrogen  in  Field  2  was  just  in  the 
same  proportion  greater. 

This  explanation,  very  simple  in  itself,  is,  however, 
opposed  by  the  fact  that  both  these  fields  manured  in 
the  same  year  with  superphosphate  of  lime  (prepared 
from  phosphorite)  (see  pp.  148  and  151),  gave  the  fol- 
lowing returns : — 

Crop,  per  hectare. 

Corn.  Straw, 

kilo.       cwt.       kilo,      cwt 

1858.  Field  1  manured  with  superphosphate  of  lime  654  =  12-8  1341  =  26'5 
1857.  "  2  "  "  1301  =  25-5  3813  =  75'0 

Hence,  by  the  application  of  three  nutritive  sub- 
stances, sulphuric  acid,  phosphoric  acid,  and  lime,  with- 
out any  increase  of  the  quantity  of  nitrogen  in  the  soil, 
as  much  corn  was  obtained  from  Field  1,  containing 
278T  kilogrammes,  nitrogen,  as  from  Field  2,  containing 
4752  kilogrammes.  There  was  then  in  the  former  as 
much  effective  nitrogen  as  in  the  latter,  but  it  was 
deficient  in  certain  other  substances  indispensably 
necessary  to  produce  an  action.  Its  power  to  become 
active  was  first  exhibited  when  these  substances  were 
added  to  the  field.  In  like  manner,  the  favourable  in- 
fluence of  superphosphate  upon  Field  2  was  exhibited  ; 
for  the  crop  of  this  plot,  when  unmanured,  did  not  cor- 
respond to  the  amount  of  active  nitrogen  which  it  con- 
tained ;  but  by  the  addition  of  superphosphate  the  crop 
rose  to  more  than  double.  And  when  to  the  super- 
phosphate upon  Field  1,  137  kilogrammes  of  common 
salt,  and  755  kilogrammes  sulphate  of  soda  were  added, 
there  was  a  still  greater  increase,  i.  e.  there  were  now 
700  kilogrammes  of  corn,  and  1550  kilogrammes  of 
straw,  a  still  greater  quantity  of  apparently  inactive 
nitrogen  having  been  rendered  effective. 

The  intelligent  farmer  who  reflects  upon  questions 
of  this  kind,  will  be  led  to  the  conclusion,  that  an  essen- 
tial difference  may  exist  between  his  own  practical 
experience  and  the  theories  of  the  school  which  seeks  to 


CAUSE   OF   INACTIVITY    OF   NITROGEN   IN    SOILS.        301 

explain  them.  When  practice  tells  us  that  farm-yard 
manure,  guano,  and  bone  earth  have  restored  or  in- 
creased the  crops  in  certain  cases,  no  one  can  maintain 
that  these  are  not  real  facts,  or  are  not  trustworthy. 
,But  the  observations  of  the  practical  man  extend  no 
further  than  these  facts  ;  he  has  not  actually  remarked 
that  the  increased  crops  were  produced  by  the  ammonia 
in  the  farm-yard  manure,  or  by  that  in  the  guano,  or  by 
the  nitrogen  in  the  nitrate  of  soda  ;  all  this  he  is  led  to 
believe  by  persons  who  themselves  know  nothing  about 
the  matter. 

It  is  certainly  a  most  remarkable  circumstance,  oc- 
curring in  no  other  trade  or  industry,  that  in  most  cases 
the  farmer  cherishes  representations  or  theories,  for  the 
truth  of  which  he  has  no  evidence  ;  nay,  he  seems  even 
to  give  up  completely  the  very  idea  of  inquiring  into 
their  correctness.  It  is  quite  incomprehensible  that  he 
should  allow  himself  to  be  guided  and  convinced  by 
facts  which  have  not  been  remarked  by  himself  upon 
his  own  ground,  but  have  been  observed  in  altogether 
different  districts,  and  which  must  at  least  remain 
doubtful  as  far  as  their  application  to  his  own  land  is 
concerned. 

If,  during  the  last  ten  years,  only  one  farmer  in  a 
thousand  had  resolved  to  institute  experiments  upon  his 
own  land  with  ammonia  or  salts  of  ammonia  to  test  the 
theory,  whether  in  fact  this  manure  is  useful  beyond  all 
others  in  increasing  the  corn  crops,  how  soon  and  how 
easily  would  an  accurate  estimate  have  been  formed  of 
its  true  value  by  other  farmers  ! 

The  simple  reflection  that  not  one  of  the  substances 
nutritive  to  plants  does  of  itself  exert  any  influence 
upon  their  growth,  and  that  several  other  substances 
must  be  present,  if  the  first  is  to  prove  useful,  should 
have  brought  him  to  the  conclusion  that  the  case  cannot 
be  otherwise  with  nitrogen ;  and  that  the  value  of  a 
manure  cannot  be  measured  by  the  amount  of  nitrogen 
which  it  contains ;  for  this  presupposes  that  the  nitro- 
gen possesses  an  operative  power,  which  must  manifest 
^tself  under  all  circumstances,  and  that  the  money 


302  AMMONIA   AND   NITKIC    ACID. 

which  the  farmer  lays  out  in  its  purchase  will  always 
ensure  an  adequate  return. 

Now,  when  his  common  sense  tells  him  that  such  a 
supposition  is  impossible,  and  that  he  has  only  to  open 
his  eyes  to  observe  by  innumerable  facts  that  ammonia 
is  no  exception  to  other  nutritive  substances,  he  will  of 
himself  come  to  the  conclusion  that  the  inactivity  of 
the  great  mass  of  nitrogen  in  his  field  is  not  due  to  any 
condition  peculiar  to  itself,  which  science  can  neither 
investigate  nor  explain,  but  that  it  is  inactive,  just  as 
phosphoric  acid,  potash,  lime,  magnesia,  silicic  acid,  and 
iron,  are  inactive,  when  there  is  wanting  in  the  ground 
one  of  the  conditions  necessary  to  make  'them  available. 

The  theory  that  by  far  the  greater  portion  of  the 
nitrogen  in  the  ground  is  incapable  of  serving  for  the 
nutrition  of  plants,  cannot  be  proved  by  the  fact  that 
the  crops  do  not  bear  any  proportion  to  the  amount  of 
nitrogen  in  the  soil ;  for  were  this  the  case,  then  all 
soils  must  be  equally  abundant  in  all  other  conditions 
for  the  growth  of  plants,  and  everywhere  possess  the 
same  geological  and  mechanical  condition.  But  this 
assumption  is  impossible,  for  on  the  whole  surface  of 
the  globe  there  are  not  two  districts  in  which  the  soils 
are  identical  in  these  respects. 

This  theory  must  be  strenuously  opposed,  not  only 
because  it  is  false  generally,  and  that  it  has  never  yet 
been  proved  to  be  true  even  in  a  single  case,  but  still 
more  on  account  of  the  pernicious  influence  which  it 
exercises  upon  the  practice  of  the  farmer.  For  since  it 
induces  him  to  suppose  that  it  is  impossible  to  give  the 
necessary  efficacy  to  the  store  of  nitrogen  in  his  land, 
he  will  never  think  even  of  attempting  to  do  so.  Being 
convinced  beforehand  that  he  need  not  try  to  raise  the 
treasure  buried  in  his  field,  he  never  even  makes  the 
attempt. 

Since  the  exact  observation  made  in  the  cultivation 
of  entire  countries  and  divisions  of  the  globe  for  centu- 
ries past,  and  also  well-established  facts,  make  it  prob- 
able that  a  source  of  nitrogenous  food  exists,  which  en- 
sures annually  to  a  cultivated  field  without  the  husband- 


SUPPLY    OF    AMMONIA   FEOM   THE   AIE.  303 

man's  aid  the  return  of  a  portion  of  the  nitrogen,  and  in 
a  rotation  the  whole  amount  of  that  substance  which 
has  been  taken  away  in  the  crops ;  and  further,  that 
the  field  may  be  exhausted  of  every  other  nutritive  sub- 
stance, however  great  its  store  in  the  ground  may  be, 
because  they  are  never  spontaneously  restored  to  the 
soil  by  nature — whereas  this  can  never  happen  to  nitro- 
gen ;  then  it  is  contrary  to  all  the  rules  of  logic  in  any 
given  case,  to  ascribe  without  closer  examination  the 
exhaustion  of  a  soil  above  all  other  things  to  a  loss  of 
nitrogen. 

We  might  suppose  that,  apart  from  the  suggestions 
of  common  sense,  the  palpable  advantage  which  would 
accrue  to  the  farmer  imperatively  demands  that  he 
should  take  all  possible  pains  to  verify  the  correctness 
of  this  fact,  and  to  discover  how  much  nitrogenous 
food  is  annually  restored  to  him  by  the  atmosphere. 
For  when  he  knows  how  far  upon  the  whole  he  may 
calculate  upon  this  source,  he  can  easily  arrange  his 
system  of  cultivation  to  make  it  most  profitable  to  him. 
If  the  atmosphere  supplies  him  with  the  whole  amount 
of  nitrogen  which  he  removes  from  his  field  by  a  rota- 
tion, then  he  can  direct  his  thoughts  to  the  means  of 
keeping  his  whole  farming  operations  going  in  the  most 
effectual  manner  with  the  store  which  he  annually  col- 
lects in  his  manure  heap,  without  spending  any  money 
upon  nitrogenous  food  for  his  plants.  If  he  finds  that 
the  atmosphere  restores  only  a  portion  of  that  which 
has  been  taken  away,  and  he  accurately  knows  what 
this  portion  amounts  to,  then  as  circumstances  require, 
he  can,  with  judicious  economy,  supply  from  other 
sources  what  is  lacking ;  or  he  may  so  arrange  his  sys- 
tem of  cultivation  as  to  make  the  supply  of  nitrogen 
from  natural  sources  cover  what  is  removed  in  the 
crops. 

Every  advance  in  an  industrial  pursuit  has  a  definite 
standard  of  value  in  the  price  of  the  products ;  and  no 
sensible  man  would  call  an  alteration  in  the  mode  of 
conducting  a  business  by  the  name  of  improvement, 
unless  the  price  of  the  products  covered  the  cost  of  pro- 


304  AMMONIA  AND   NITRIC   ACID. 

duction.  When  the  price  of  guano  exceeds  a  certain 
limit,  so  that  the  crop  realised  does  not  bear  a  proper 
proportion  to  the  outlay  of  capital  and  labour,  this  very 
circumstance  prevents  its.  application. 

From  this  point  of  view  farmers  might  long  ago 
have  perceived  that  the  question  about  the  necessity  of 
supplying  ammonia  to  increase  the  crops  of  corn,  in- 
cludes another  question,  whether,  on  the  whole,  prog- 
ress in  this  respect  is,  or  is  not,  possible  in  agricultural 
practice. 

A  few  considerations  only  are  necessary  to  bring 
the  farmer  to  the  conviction,  which  I  myself  entertain, 
that  if  increased  production  depends  upon  an  augmen- 
tation of  nitrogenous  food  in  the  soil,  we  must  at  once 
renounce  all  idea  of  improvement.  For  my  own  part, 
I  am  much  more  inclined  to  believe,  that  progress  is 
only  possible  and  attainable  if  the  farmer  restricts  him- 
self to  that  store  of  nitrogen  which  he  can  collect  upon 
his  own  ground,  avoiding  as  much  as  possible  all  pur- 
chase of  nitrogenous  food  from  other  quarters. 

On  the  average,  all  the  experiments  of  Lawes  in 
England  have  shown,  that/b/*  one  pound  of  salts  of  am- 
monia in  manures,  two  pounds  of  ivheat  may  ~be  reaped. 

These  results,  we -must  remember,  were  obtained 
from  a  field  in  which  one  acre  without  manure  of  any 
kind  was  able  to  yield,  for  seven  years  consecutively, 
1125  Ibs.  of  corn  and  1Y56  Ibs.  of  straw ;  and  that  all 
the  plots  manured  with  salts  of  ammonia  also  received 
phosphate  and  silicate  of  potash.* 

On  an  average,  Lawes  manured  his  fields  with  3 
cwt.  of  salts  of  ammonia,  and  thereby  he  obtained  half 
as  much  corn  again  as  the  unmanured  plot  yielded. 

We  will  now  assume  that  the  extra  crop  obtained 
was  exclusively  due  to  the  salts  of  ammonia ;  we  will 

*  On  this  point  Lawes  says  ('  Journal  of  the  Royal  Agr.  Soc.  of  Eng.,' 
v.  xiv.  p.  282),  that  for  the  production  of  one  bushel  of  wheat  (=64  to  65 
pounds,  containing  1  pound  of  nitrogen)  which  the  soil  was  made  to  yield 
above  its  natural  power,  5  pounds  of  ammonia  were  requisite  (•  =  16  pounds 
of  sal  ammoniac,  or  20  pounds  of  sulphate  of  ammonia).  He  adds,  how- 
ever, that  in  no  single  experiment -did  the  extra  crop  obtained  correspond 
to  this  estimate. 


CALCULATION   OF   AMMONIA   KEQUIKED   FOR   SAXONY.      305 

further  suppose  that  all  soils  are  inexhaustible  in  phos- 
phoric acid,  potash,  lime,  &c. ;  and  consequently,  that 
the  continuous  application  of  salts  of  ammonia  would 
involve  no  exhaustion  of  the  soil.  If  we  now  reckon 
how  much  salts  of  ammonia,  by  weight,  would  be 
necessary  for  the  kingdom  of  Saxony,  in  order  to  obtain 
half  as  much  corn  again  as  the  unmanured  land  pro- 
duces, the  result  is  the  following : — The  kingdom  of 
Saxony  comprised,  in  the  year  1843,  1,344,474:  acres 
(1  acre  =  1'368  Eng.  acre)  of  arable  land,  exclusive  of 
vineyards,  gardens,  and  meadows.  If  we  suppose  that 
each  acre  yields  one  corn-crop  in  two  years,  and  that  4 
cwt.  salts  of  ammonia  had  to  be  applied  in  the  way  of 
manure,  the  kingdom  of  Saxony  would  require  annually 
2,688,958  cwt.  —  134,447  tons  of  salts  of  ammonia. 

Those  who  possess  even  a  slender  acquaintance  with 
chemical  manufacture,  and  know  from  what  raw  ma- 
terials (animal  refuse  and  gas  water)  salts  of  ammonia 
are  procured,  must  easily  see  that  all  the  manufactories 
in  England,  France,  and  Germany  put  together,  could 
not  produce  so  much  as  the  fourth  part  of  the  salts  of 
ammonia  required  by  comparatively  a  very  small  coun- 
try, in  order  to  increase  its  products  in  the  manner  pro- 
posed. 

With  a  similar  distribution  we  can  easily  calculate 
how  much  salts  of  ammonia  would  be  required  for  the 
German  provinces  of  Austria  with  11  million  jochen 
(1  joch  =  1-422  Eng.  acre)  of  arable  land  ;  for  Prussia, 
with  33  million  morgen  (1  morgen  —  0'631  Eng.  acre) ; 
for  Bavaria,  with  9  million  tagwerk  (1  tagwerk  =  0*842 
Eng.  acre) ;  and  even  if  it  were  possible  to  quadruple 
the  manufacture  of  salts  of  ammonia,  this  would  have 
no  material  influence  upon  the  crops. 

The  cheapest  ammonia  is  conveyed  to  Europe  in 
Peruvian  guano,  which,  taking  a  high  average,  contains 
16  per  cent. 

Peruvian  guano  is  principally  used  in  the  cultivated 
lands  of  Europe,  as  in  England,  France,  the  Scandina- 
vian countries,  Belgium,  the  Netherlands,  Prussia,  and 
the  German  States,  comprising,  exclusive  of  Austria, 


306  AMMONIA  AND   NITRIC  ACID. 

120  millions  of  inhabitants.  Now  if  we  suppose  that 
upon  these  lands  for  centuries  to  come  6  million  cwt. 
(  =  300,000  tons)  of  Peruvian  guano,  containing  360,- 
000  cwt.  of  ammonia,  were  annually  applied,  and  that 
it  was  possible,  with  the  means  at  present  at  our  dis- 
posal, by  5  Ibs.  of  ammonia  to  raise  65  Ibs.  additional  of 
wheat,  or  its  equivalent  value,  then  the  increased  crop 
of  corn  would  just  reach  so  far  as  to  give  each  individ- 
ual in  the  community  2  Ibs.  of  corn  a  day  for  two  days 
in  the  year. 

If  we  assume  2  Ibs.  of  corn  or  its  equivalent  to  be 
the  average  amount  of  nutriment  required  by  an  indi- 
vidual, this  makes  730  Ibs.  annually.  According  to 
the  supposition  made  above,  36  million  pounds  of  am- 
monia would  produce  thirteen  times  as  much  =  468 
million  pounds  of  corn  or  its  equivalent,  whereby  641,- 

000  individuals  could  be  nourished  for  a  year. 
Supposing  the  population  of  England  and  Wales  to 

increase  only  1  per  cent,  annually,  this  makes  200,000 
individuals  in  one  year,  and  600,000  in  three  years. 
Now  the  cereals  hypothetically  raised  by  help  of  the 
ammonia  in  6  million  cwt.  of  guano  imported  from 
abroad,  would  suffice  but  very  few  years  to  support  the 
increased  population  of  England  and  Wales. 

And  what  would  be  the  state  of  things  six  or  nine 
years  afterwards  in  England  or  Europe,  if  we  were 
actually  dependent  upon  a  foreign  importation  of  am- 
monia, for  the  support  of  the  increasing  population? 
Could  we  import  12  million  cwt.  of  guano  in  six  years, 
or  18  million  in  nine  years  ? 

We  know  most  positively,  that  in  a  few  years  the 
source  of  ammonia  in  guano  will  be  exhausted ;  that 
we  have  no  prospect  of  discovering  a  new  and  richer 
source  ;  that  the  annual  increase  of  population,  not  only 
in  England  but  in  all  European  countries,  is  more  than 

1  per  cent.  ;  and,  finally,  that  in  proportion  to  the  in- 
crease in  the  population  in  the  United  States,  Hungary, 
&c.,  a  corresponding  diminution  must  follow  in  the  ex- 
portation of  corn  from  those  countries.     From  these 
considerations  the  hope  of  augmenting  the  crops  of  a 


COST   OF  AMMONIA.  307 

country  by  the  importation  of  ammonia  must  appear 
utterly  vain. 

In  Germany,  a  pound  of  wheat  costs  at  present  4 
kreutzers  (1-J<#.) ;  a  pound  of  sulphate  of  ammonia,  9 
kreutzers  (3%d.) ;  and  if  it  were  possible  with  a  pound 
of  this  salt,  added  to  our  ordinary  manures,  to  produce 
2  pounds  more  of  wheat,  then  for  every  outlay  of  one 
florin  (2s.)  in  money,  the  German  farmer  would  receive 
53  kreutzers  (Is.  9d.)  in  corn.  This  relation  of  outlay 
,to  income  is  evidently  well  known  in  practice,  for  up  to 
this  moment  salts  of  ammonia  have  nowhere  come  into 
general  use ;  and  though  many  manufacturers  of  ma- 
nure add  a  certain  quantity  of  ammonia  to  their  produc- 
tions, this  is  chiefly  to  humour  the  fancy  of  farmers  for 
this  substance  ;  but  none  of  them  can  tell  what  advan- 
tage results  from  this  addition.  This  prejudice  will 
soon  disappear  of  itself,  when  farmers  have  learned  to 
make  a  proper  use  of  the  nitrogenous  food  which  nature 
supplies  spontaneously  to  the  land  without  any  aid  on 
their  part. 

The  abundant  supply  of  nitrogenous  food  in  the 
soil,  the  increase  of  the  same  in  well-cultivated  ground, 
the  examination  of  rain-water  and  of  the  atmosphere, 
all  facts  observed  in  cultivation  in  general,  prove  that, 
even  with  the  highest  system  of  farming,  the  soil  is  not 
exhausted  in  its  store  of  nitrogenous  food,  and  that  con- 
sequently there  is  a  circulation  of  nitrogen,  like  that  of 
carbon,  which  presents  to  the  farmer  the  possibility  of 
increasing  his  store  of  active  nitrogen  in  the  soil. 

The  extraordinary  effect  of  superphosphate  of  lime 
in  augmenting  the  crops  of  corn,  turnips,  and  clover, 
almost  without  exception,  upon  all  German  lands  to 
which  these  non-azotised  manures  have  been  applied ; 
the  operation  of  the  newly-introduced  Baker  and  Jarvis 
guanos*  (which  contain  no  ammonia) ;  the  action  of 
lime,  salts  of  potash,  gypsum,  &c.,  all  show  without 
doubt  that  an  accumulation  of  nitrogenous  food  has 
taken  place  in  the  soil,  the  source  of  which  was,  until 
lately,  quite  obscure. 

*  From  a  communication  in  the  '  Official  Gazette,'  No.  3,  of  1st  March, 


308  AMMONIA   AND   NITRIC   ACID. 

We  had  reason  enough  to  believe  in  a  partial  resto- 
ration to  the  soil  of  nitrogenous  food  by  air  and  rain, 
bat  that  it  should  be  augmented  was  quite  unexplained  ; 
because  this  presupposed  that  ammonia  and  nitric  acid 
were  produced  from  the  nitrogen  of  the  atmosphere,  in 
evidence  of  which  we  had  no  facts  whatever  Very 
recently  this  source  of  the  increase  of  the  nitrogenous 
food  of  plants  was  discovered  by  Schonbein,  and  the 
problem  was  solved  in  the  most  unexpected  manner. 

In  his  experiments  upon  oxygen,  Schonbein  found 
that  the  white  fume  emitted  by  a  piece  of  moist  phos- 
phorus is  not,  as  was  previously  believed,  phosphoric 
acid,  but  nitrate  of^  ammonia.  1  myself  had  an  oppor- 
tunity of  seeing  this  proved  at  a  lecture,  illustrated  by 
experiments,  which  Schonbein  delivered  at  Munich  in 
the  summer  of  1860.  It  is  probable,  as  he  states,  that 
in  this  reaction  the  nitrogen  of  the  atmosphere,  by  a 
kind  of  induction,  'combines  with  three  equivalents 
of  water,  whereby  on  the  one  hand  nitrous  acid,  and 
on  the  other  ammonia,  are  formed ;  just  as  is  well 
known  that  under  the  influence  of  a  higher  tempera- 
ture, nitrite  of  ammonia  is  decomposed  into  wrater  and 
nitrogen  gas.  The  most  striking  fact  is,  this  salt  is 
formed  under  circumstances  which  we  should  have  been 
led  to  suppose  were  precisely  those  opposed  to  its  for- 
mation ;  but  the  production  of  the  peroxide  of  hydrogen 
(so  easily  decomposed  by  heat),  during  the  slow  oxida- 
tion of  sether,  which  is  attended  by  a  perceptible  evolu- 
tion of  heat,  is  a  fact  not  less  certain,  and  hitherto 
equally  unexplained. 

The  formation  of  nitrite  of  ammonia  during  this  slow 
process  of  oxidation  made  it  probable  that  it  takes  place 
everywhere  on  the  earth's  surface  where  oxygen  enters 

1862,  for  the  Agric.  Union  in  Saxony,  the  following  crops  per  acre  were 
obtained  in  1861 : — 

Wheat. 

Corn.  Straw. 

3  cwt.  Jarvis  guano  produced    2244  Ibs.  4273  Ibs. 

3     "     Baker      "  "  2929    "  5022    " 

6     "    steamed  bones    "  3015    "  4755    « 

Unmanured  "  1955    "  3702    " 


FORMATION   OF   NITRITE   OF   AMMONIA.  309 

into  combination  ;  and  consequently  that  the  same  pro- 
cess, whereby  carbon  is  converted  into  carbonic  acid, 
forms  also  an  ever-renewing  source  of  nitrogenous  food 
for  plants. 

Soon  afterwards,  Kolbe  showed  ('  Annal.  d.  Cliem. 
u.  Pharm.'  bd.  119,  s.  176)  that  if  a  name  of  hydrogen 
gas  is  allowed  to  burn  in  the  open  neck  of  a  flask  con- 
taining oxygen,  the  interior  is  filled  with  the  red  fumes 
of  nitrous  acid.* 

Further,  Boussingault  observed  that,  in  the  con- 
sumption of  common  illuminating  gas,  the  water  in 
Lenoirs  gas  machine  contained  ammonia  and  nitric 
acid ;  and  shortly  after,  Bottger  mentioned,  in  the 
4  Annual  Keport  of  the  Physical  Society  of  Frankfort ' 
(meeting  of  Nov.  2,  1861),  that,  according  to  his  experi- 
ments, not  only  in  the  case  of  hydrogen,  but  generally 
when  hydro-carbons  were  burned,  a  certain  quantity  of 
nitrite  of  ammonia  was  always  formed,  together  with 
water  and  carbonic  acid.  Almost  contemporaneously 
with  this  notice,  I  received  from  Schonbein  a  written 
communication  announcing  the  very  same  results  which 
he  had  obtained  in  the  same  way,  so  that  no  doubt  can 
remain  as  to  the  correctness  of  this  fact. 

The  practical  farmer,  who  is  really  anxious  to  im- 
prove his  method  of  cultivation,  must  be  led  by  these 
undoubted  facts  to  determine  upon  ascertaining,  with 
the  greatest  clearness,  the  effect  of  nitrogen  in  his  ma- 
nures. Before  he  lias  been  convinced  that  the  atmos- 
phere and  rain  convey  the  necessary  amount  of  nitro- 
genous food  to  his  plants,  no  one  could  expect  him  to 
renounce  the  employment  of  ammonia  as  a  manure. 
When  it  is  asserted  that  a  farmer  can  give  a  maxi- 
mum of  fertility  to  his  land  without  supplying  to  it  any 
nitrogenous  matter,  it  is  not  meant  that  he  must  re- 
nounce the  use  of  farm-yard  manure  ;  but  the  assertion 
implies  the  existence  of  the  latter,  and  is,  in  fact,  based 
upon  it. 

For  the  restoration  or  augmentation  of  productive 

*  The  formation  of  nitrous  acid  in  eudiometrical  experiments  was 
already  known. 


310  AMMONIA   AND   NITEIC   ACID. 

power  in  exhausted  corn-fields,  it  is  absolutely  necessary 
that  the  arable  soil  should  contain  a  surplus  of  all  nutri- 
tive substances  for  cereal  plants,  nitrogenous  among 
others,  but  no  one  in  greater  proportion  than  the  rest. 
It  is  assumed  that  the  farmer  by  a  right  succession  of 
crops,  that  is,  by  a  proper  proportion  between  his  corn 
and  fodder  fields,  is  always  in  a  position,  by  carefully 
husbanding  the  ammonia  in  his  farm-yard  manure  and 
avoiding  all  unnecessary  waste,  to  provide  the  arable 
soil  with  such  a  surplus  of  nitrogenous  food  as  will  cor- 
respond to  the  proportion  of  the  other  nutritive  sub- 
stances therein  stored ;  and  that  the  atmosphere  annu- 
ally makes  up  what  he  removes  in  his  crops. 

The  nitrogenous  food  conveyed  by  the  atmosphere 
and  rain,  is  upon  the  whole  sufficient  for  his  cultivated 
plants,  but  not  enough  for  many  of  them  in  point  of 
time.  In  order  to  give  a  maximum  crop,  many  plants 
require,  during  the  period  of  vegetation,  much  more 
than  the  air  and  rain  afford  in  that  time ;  and  therefore 
the  farmer  makes  use  of  fodder  plants  in  order  to  in- 
crease the  crops  of  his  corn-fields.  The  fodder  plants, 
which  thrive  without  rich  nitrogenous  manure,  collect 
from  the  ground  and  condense  from  the  atmosphere,  in 
the  form  of  blood  and  flesh  constituents,  the  ammonia 
which  is  supplied  from  these  sources ;  and  the  farmer, 
in  feeding  his  horses,  sheep,  and  cattle  with  the  turnips, 
clover,  &c.,  receives,  in  their  solid  and  fluid  excrements, 
the  nitrogen  of  the  fodder  in  the  form  of  ammonia  and 
products  rich  in  nitrogen  ;  and  thus  he  obtains  a  supply 
of  nitrogenous  manures  or  nitrogen,  which  he  gives  to 
his  corn-fields. 

The  rule  is,  that  for  certain  plants,  weak  in  devel- 
opement  of  leaf  and  root,  and  which  have  but  a  short 
period  of  vegetation,  the  farmer  must  compensate  by 
the  quantity  of  manure  for  the  time  which  is  wanting 
for  the  absorption  of  the  requisite  amount  of  nitrogen 
from  natural  sources. 

It  is  easy  to  see  that  the  accumulation  of  nitro- 

Eenous   food  by  farm-yard  manure  in  the  uppermost 
tyers  of  the  ground,  so  very  important  for  the  perfect 


GREAT    DIVERSITY   IN   NATURE   OF    SOILS. 


311 


growth  of  cereal  plants,  must  chiefly  depend  upon  the 
successful  growth  of  fodder  plants. 

The  unmanured  fields  in  the  Saxon  experiments — 


Yielded 
altogether. 

Nitrogen. 

Lost  by 
sale  of  crop. 

Nitrogen. 

Received 
in  farm-yard 
manure. 

Nitrogen. 

Clover 
crops. 

1851-1854. 

Cunnersdorf  .  .... 

Ibs. 
342-4 

Ibs. 

78'4 

Ibs. 
263  6 

Ibs. 
9144 

279-5 

84-1 

i  7/vO 

HKOQ 

Kotitz    

160-9 

54-8 

106'1 

1  AQK 

Oberbobritzsch  

127-7 

57-2 

70-5 

911 

It  is  easily  perceived  from  this  table  that  the  quanti- 
ties of  nitrogen  which  could  be  obtained  from  the  field 
and  restored  in  the  form  of  farm-yard  manure,  bear  a 
proportion  not  exact  but  sufficiently  well  marked,  to 
the  crops  of  clover  produced  by  the  field ;  and  there 
can  be  no  doubt  that  the  farmer  who  takes  the  right 
way  to  make  his  fodder  plants  thrive,  obtains  at  the 
same  time  the  means  of  enriching  his  arable  soil  with  a 
surplus  of  nitrogenous  food  for  his  corn-plants. 

We  do  not  mean  to  imply  that  in  every  possible  case 
the  farmer  must  renounce  the  idea  of  supplying  to  his 
land  ammonia  from  other  quarters ;  for  soils  vary  so 
very  much  in  their  nature,  that  even  though  we  can 
assert  that  by  far  the  greater  proportion  of  them  may 
not  require  a  restoration  of  nitrogenous  food,  yet  this 
will  not  hold  good  for  all  without  exception.  In  a  soil 
rich  in  lime  and  humous  materials,  in  consequence  of 
the  process  of  decay  going  on,  a  certain  quantity  of  the 
ammonia  fixed  in  the  earth  is  converted  into  nitric  acid, 
which  is  not  retained  by  the  soil,  but  is  conveyed  into 
the  lower  layers  in  the  form  of  salts  of  lime 'or  mag- 
nesia. Under  certain  circumstances,  this  loss  may 
amount  to  much  more  than  is  compensated  by  the  at- 
mosphere, and  for  such  fields  a  supply  of  ammonia  will 
always  be  useful.  The  same  holds  good  for  certain  soils 
which  have  not  been  tilled  for  many  years,  and  in 


312  AMMONIA  AND  NITEIC  ACID. 

which,  by  the  operation  of  the  causes  above-mentioned, 
the  necessary  surplus  of  nitrogenous  food,  formerly 
present,  is  gradually  expended.  On  recommencing  the 
cultivation  of  such  soils,  the  employment  of  nitrogenous 
manures  will  at  first  produce  a  remarkably  beneficial 
effect.  Afterwards,  these  too  require  no  further  supply. 

There  is  one  reason  which  excites  in  the  farmer's 
mind  a  prejudice  in  favour  of  introgenous  manure,  and 
that  is  the  great  inequality  in  the  appearance  of  the 
young  crops,  when  such  manures  are  applied  in  com- 
parative experiments.  The  cereal  plants  upon  fields 
manured  with  guano  or  nitrate  of  soda  are  distinguished 
before  others  by  a  deep  green  colour,  and  by  broader 
and  more  numerous  leaves ;  but  the  harvest  is  generally 
far  from  corresponding  to  the  expectations  raised  by 
this  promising  appearance.  Upon  a  field  excessively 
rich  in  nitrogenous  food,  there  is  a  kind  of  rankness  in 
the  early  growth  like  that  produced  by  a  hot-bed  :  the 
leaves  and  stalks  are  watery  and  weak,  in  consequence 
of  the  want  of  time  in  their  over-hasty  growth  to  absorb 
contemporaneously  from  the  soil  the  necessary  quantity 
of  substances,  such  as  silicic  acid  and  lime,  capable  of 
communicating  to  their  organs  a  certain  solidity  and 
power  of  resistance  against  those  external  causes  which 
endanger  their  existence.  The  stalks  fail  to  acquire  the 
necessary  stiffness  and  strength,  and  are  always  liable 
to  be  laid,  especially  on  lime  soils. 

This  injurious  influence  of  excess  of  nitrogenous  food 
is  particularly  remarkable  in  the  case  of  the  potato 
plant ;  for  if  it  grows  upon  a  soil  excessively  rich  in 
nitrogenous  food,  and  the  temperature  should  suddenly 
fall  and  wet  weather  supervene,  the  plant  is  often  at- 
tacked by  the  so-called  potato  disease  ;  while  a  neigh- 
bouring potato  field  merely  manured  with  ashes  shows 
no  trace  of  it. 

Among  all  the  many  experiments  which  have  been 
hitherto  made  by  farmers  to  improve  their  land,  there  is 
not  one  instituted  for  the  purpose  of  ascertaining  the 
actual  condition  of  their  soil,  or  of  seeking  proofs  for 
the  correctness  of  the  notions  which  they  had  once 


PRACTICAL   FARMER   GUIDED   BY   FACTS.  313 

adopted.  The  reason  of  their  indifference  about  obtain- 
ing proofs  for  their  views  chiefly  consists  in  this,  that 
the  practical  man,  like  the  artisan,  is  guided  in  his  busi- 
ness not  by  ideas,  but  by  facts.  Hence  it  is  quite  in- 
different to  him,  whether  the  theory,  or  what  he  dig- 
nifies by  that  name,  is  correct  or  not,  as  he  does  not 
regulate  his  proceedings  in  accordance  with  it. 

Many  thousand  farmers,  who  have  not  the  remotest 
conception  of  the  nutrition  of  plants  or  the  composition 
of  manures,  apply  guano,  bone  earth,  and  other  ma- 
nures, to  their  fields,  with  fully  the  same  effect  and 
with  even  the  same  skill  as  others  who  possess  such  in- 
formation ;  nor  do  the  latter  derive  any  manifest  ad- 
vantage from  their  knowledge,  because  it  is  not  of  the 
right  kind  ;  for  example,  the  chemical  analysis  of  ma- 
nures is  rather  calculated  for  ascertaining  their  purity, 
and  for  determining  their  price,  than  as  a  means  for 
making  us  acquainted  with  their  effect  upon  land. 

In  England  bone  earth  wras  used  and  valued  as  a 
manure  half  a  century  before  any  idea  was  formed  as  to 
what  its  operation  was  due  ;  and  when  afterwards  the 
erroneous  theory  was  adopted  that  its  effect  depended 
upon  the  nitrogenous  gelatine  which  it  contained,  this 
view  did  not  exert  the  slightest  influence  upon  its  em- 
ployment. 

The  farmer  manured  his  field  with  bone  earth,  not 
on  account  of  its  nitrogen,  but  because  he  wished  to 
have  larger  crops  of  corn  and  fodder,  and  because  ex- 
perience told  him  that  he  could  not  expect  them  with- 
out bone  earth. 

An  agricultural  practice,  founded  upon  a  simple  ac- 
quaintance with  facts,  without  any  idea  of  their  nature, 
or  one  based  on  the  exhaustion  of  the  land,  may  be  con- 
ducted by  a  person  of  very  limited  intelligence,  nay, 
the  most  ignorant  man  may  be  fitted  for  the  purpose, 
by  the  mere  statement  of  facts  to  him.  But  a  rational 
pursuit  of  agriculture,  which,  with  the  greatest  economy 
of  capital  and  labour,  can  obtain  from  a  field  continu- 
ously without  exhaustion  the  highest  crops  it  is  capable 
of  yielding,  requires  a  large  compass  of  knowledge, 

14 


314  AMMONIA  AND   NITEIC   ACID. 

observation,  and  experience,  more  perhaps  than  in  any 
other  business.  For  the  rational  agriculturist  must  not 
merely  know  all  the  facts  with  which  the  illiterate  peas- 
ant is  acquainted,  but  he  must  also  be  able  to  appre- 
ciate them  at  their  proper  value ;  he  must  know  the 
reason  of  all  his  proceedings,  and  what  effect  they  may 
have  upon  his  land.  He  must  be  able  to  interpret  what 
his  field  tells  him  in  the  phenomena  which  he  observes 
in  practice ;  in  a  word,  he  must  be  a  thorough  man, 
and  not  a  half-and-half  creature  who  knows  no  more 
about  his  actions  than  a  tom-cat,  with  just  skill  enough 
to  catch  gold  fish  in  a  basin  of  water.* 

*  If  we  compare  the  theoretical  views  expressed  in  the  works  of  con- 
fessedly good  practical  farmers  with  the  system  of  husbandry  which  they 
have  found  by  their  own  experience  to  be  the  best,  we  observe  the  most 
irreconcilable  contradictions  between  the  two. 

Walz  ('Communications  'from  Hohenheim,'  No.  3,  1857)  disputes  both 
these  propositions,  viz. : — 

4  That  the  removal  of  the  mineral  constituents  in  the  crops,  without 
compensation,  produces  sooner  or  later  lasting  unfruitfulness  as  a  conse- 
quence.' 

'  That  if  a  soil  is  to  maintain  its  fertility  continuously,  the  removed 
mineral  constituents  must,  sooner  or  later,  be  returned  to  it,  i.e.  the  com- 
position of  the  soil  must  be  restored.' 

And  gives  as  his  opinion  that  both  these  propositions  are  at  present  appli- 
cable only  to  soils  of  the  worst  kind,  which  needed  a  supply  of  mineral 
matters  from  the  very  beginning. 

Now,  if  we  turn  to  the  '  Application  of  his  theory  to  practice '  (page 
117),  we  would  naturally  suppose  that  he  would  never  trouble  himself 
about  any  compensation  ;  but  it  soon  appears  that  he  is  far  from  believing 
in  the  truth  of  his  own  doctrines.  He  lays  the  proper  stress  upon  the 
restoration  of  potash,  lime,  magnesia,  phosphoric  acid,  gypsum,  guano, 
bone-earth,  marl,  and  farm-yard  manure;  and  lays  down  the  following 
rule : — '  That  the  farmer,  to  keep  his  ground  in  uniformly  increasing  fer- 
tility, must  not  remove  more  in  his  crops  than  the  products  of  the  atmos- 
phere and  the  assimilable  mineral  substances  added  annually  to  the  soil 
by  the  action  of  the  weather.'  He  says  further : — '  If  the  farmer  were  to 
confine  his  business  entirely,  e.g.  to  the  manufacture  of  bee r,  spirit,  sugar, 
starch-meal,  dextrine,  vinegar,  &c.,  and  the  sale  of  animal  products  merely 
to  butter,  using  up  the  skimmed  milk  ;  if  for  his  dairy  he  were  to  buy  none 
but  full-grown  cows  and  not  breed  them  himself,  thus  endeavouring  to 
keep  the  phosphates  upon  his  farm,  then  he  would  not  only  preserve  con- 
tinually the  mineral  substances  in  his  store  of  manure,  but  he  would  also 
increase  them  by  the  yearly  process  of  disintegration,  unless  he  preferred 
to  alienate  the  latter  in  his  produce '  (s.  142). 

Hence  the  point  of  his  practical  teaching,   in  direct  opposition  to  his 


A   RATIONAL   AGRICULTURIST.  315 

theoretical,  is  that,  in  order  to  obtain  uniform  crops,  great  care  must  be 
taken  to  maintain  and  restore  the  composition  of  the  soil. 

The  practical  man  proves  that  the  notions  which  he  has  conceived  are 
entirely  inapplicable  in  his  practice ;  and  that  the  scientific  principles 
which  he  disputes  are  precisely  those  by  which  he  is  unconsciously  guided. 
Sound  practice  and  true  science  are  ever  in  unison ;  and  a  contest  on  these 
matters  is  possible  only  between  two  persons,  one  of  whom  does  not  under- 
stand the  other.  The  chief  fault  lies  in  want  of  precision  in  defining 
things,  and  in  using  indefinite  or  vague  language  to  express  our  ideas. 

The  opinion  of  Rosenberg-Lipinsky  (see  his  'Practical  Agriculture/ 
b.  ii.  Breslau:  E.  Trewends,  1862),  is  'that  no  kind  of  plant  actually 
exhausts  the  great  storehouse  of  the  soil'  (p.  738);  and  further,  'that 
plants,  directly  and  indirectly,  return  to  the  soil  more  strength  than  they 
take  from  it '  (p.  740).  This  opinion  is  thus  modified  (p.  742) : — '  when 
therefore  the  farmer  does  not  take  sufficient  care  that  the  more  important 
magazine  of  nutriment,  the  soil,  receives  at  the  right  time,  and  in  proper 
quantity,  the  necessary  compensation  for  that  which  is  inevitably  consumed, 
the  picture  of  exhaustion  which  the  cultivated  plants  manifestly  wear, 
cannot  possibly  be  charged  upon  their  consumers,  but  the  blame  is  wholly 
and  solely  attributable  to  the  farmer  himself.'  Further,  at  p.  740,  he  says, 
'  Only  in' those  plains,  where  the  injustice  of  the  elements,  or  of  man,  has 
violently  disturbed  the  natural  laws  of  the  nutrition  of  plants,  does  the 
scanty  vegetation  of  the  wild  flora  indicate  the  exhaustion  of  the  soil.' 


CHAPTEE   XII. 

COMMON   SALT,   NITKATE   OF   SODA,    SALTS   OF  AMMONIA, 
GYPSUM,    LIMK. 

Effect  of  these  substances  as  elements  of  food  ,  their  effect  on  the  condition  of  the 
soil — Kuhlmann's  experiments  with  common  salt,  nitrate  of  soda,  and  salts  of 
ammonia ;  experiments  with  the  same  substances  in  Bavaria ;  conclusions : 
these  matters  are  elements  of  food  ;  they  are  chemical  means  for  preparing  the 
soil ;  they  cause  the  distribution  of  the  food  in  the  soil  in  the  form  proper  for 
the  growth  of  plants — Experiments  by  Pincus  with  gypsum  and  sulphate  of 
magnesia  on  clover;  decrease  of  flowers  and  increase  of  stem  and  leaves  of 
clover  by  sulphates  ;  the  crop  is  not  in  proportion  to  the  quantity  of  sulphates 
used— Effect  of  gypsum  not  yet  explained  ;  indication  in  the  comportment  of 
clover  soils  with  solution  of  gypsum  ;  such  solution  disperses  potash  and 
magnesia  in  the  soil— Manures,  their  effect  not  explained  by  the  composition  of 
plants  produced  by  them — Composition  of  the  ash  of  clover  manured  with  dif- 
ferent substances — Effect  of  lime  ;  experiments  of  Kuhlmann  and  Triiger  ; 
comportment  of  lime-water  with  soils. 

THESE  salts  are  employed  in  agriculture  in  many 
cases  with  marked  success  as  manure ;  and  since 
nitric  acid,  soda,  ammonia,  sulphuric  acid,  and  lime, 
are  nutritive  substances,  the  explanation  of  their  efficacy 
presents  no  difficulty.  But  they  also  possess  other 
peculiarities,  by  which  they  aid  and  promote  the  action 
of  the  plough  and  of  mechanical  tillage,  as  well  as  the 
influence  of  the  atmosphere  upon  the  condition  of  the 
field.  This  influence  is  not  always  clear  to  our  minds, 
but  it  is  not  less  certain. 

We  have  every  reason  to  believe  that  where  the 
crops  are  increased  by  manuring  with  common  salt 
alone,  or  when  the  favourable,  influence  of  salts  of  am- 
monia or  nitrate  of  soda  is  augmented  by  the  addition 
of  common  salt,  the  operation  of  the  three  salts  essen- 
tially depends  upon  their  power  of  diffusing  the  nutri- 
tive substances  present  in  the  soil,  or  of  preparing  those 
substances  for  absorption.  In  what  manner  this  takes 
place  with  all  is  not  yet  explained.  The  first  trust- 


COMMON   SALT  WITH   SALTS   OF  AMMONIA. 


317 


worthy  experiments  in  this  direction  were  made  by  F. 
Kiihlmann  (<  Annal  de  Chim.'  3  ser.  t.  xx.,  p.  279).  In 
the  year  1845  he  manured  a  natural  meadow  with  sal 
ammoniac,  sulphate  of  ammonia,  and  common  salt ; 
and  obtained  the  following  quantities  of  hay  : — 

Crop  of  hay  per  hectare,  1845  and  1846. 

Increased  crop. 

Unmanured  11263  kilos.       — 

Sal  ammoniac,  yearly  200  kilos 14964     "        3700  kilos. 

U  ((  linn        U  ) 

Common  salt     «        200    "      }  -169BO    '         868> 

Another  meadow  yielded  : — 

Crop  of  hay,  per  hectare,  1846. 

Increased  crop. 

Unmanured  3323  kilos.       — 

Sulphate  of  ammonia  200  kilos -  5856     "         2533  kilos. 

"  "  900      "        ) 

Common  salt   183    "      }  -  6496  3173 

For  the  purpose  of  examining  the  effect  of  common 
salt  upon  cereals,  the  General  Committee  of  the  Agri- 
cultural Society  ia  Bavaria  instituted  at  Bogenhausen 
and  Weihenstephan,  in  the  years  1857  and  1858,  a  series 
of  experiments,  conducted  thus :  of  two  plots,  the  one 
was  manured  with  salts  of  ammonia,  the  other  with  the 
same  quantity  of  salts  of  ammonia  and  an  addition  of 
3080  grammes  of  common  salt.  These  experiments 
were  described  at  page  286,  and  it  will  be  sufficient 
here  to  quote  the  crops  which  were  obtained  with  salts 
of  ammonia  alone,  and  with  common  salt  added  to  salts 
of  ammonia. 

Bogenhausen,  1857. 


Barley. 

Manur 

salts  of  E 

Corn. 

ed  with 

iiumonia. 

Straw. 

Manured  with  common  salt 
and  salts  of  ammonia. 

Corn. 

Straw. 

Plot    I.    , 

Grammes. 
6355 
8470 
7280 
6912 

Grammes. 
16205 
16730 
17920 

18287 

Grammes. 
14550 
16510 
9887 
11130 

Grammes. 
27020 
36645 
24832 
27969 

"    II 

"  III  

"IV  

318     SALT,   NITRATE  OF   SODA     SALTS   OF  AMMONIA     ETC. 


Bogenhausen,  1858  (p.  287). 


Winter-wheat. 

Manured  with 
salts  of  ammonia. 

Manured  with  common  Bait 
and  salts  of  ammonia. 

Corn. 

Straw. 

Corn. 

Straw. 

Plot   I 

grammes. 
196(50 
21520 
25040 
27090 

grammes. 
41440 
38940 
57860 
65100 

grammes. 
29904 
31696 
31416 
34832 

grammes. 
61040 
71960 
74984 
74684 

"II    

"  III  

"IV         ..... 

In  both  these  series  of  experiments,  the  crops  of 
corn  and  straw  were  remarkably  increased  by  the  addi- 
tion of  common  salt ;  and  it  is  scarcely  necessary  to 
repeat,  that  such  an  augmentation  could  not  possibly 
have  taken  place  unless  the  soil  had  contained  a  certain 
quantity  of  phosphoric  acid,  silicic  acid,  potash,  &c., 
capable  of  being  brought  into  operation,  but  which 
without  common  salt  was  not  assimilable. 

Similar  experiments  were  undertaken  by  the  same 
society  in  Weihenstephan  with  nitrates  ;  and  the  crops 
produced  by  these  salts  alone,  and  with  the  addition  of 
common  salt,  per  hectare,  were  as  follows : — 

Weihenstephan,  1857. — Summer  barley. 


I. 

Unmanured. 

II. 

Nitrate  of 
soda. 

III. 
Nitrate  of 
soda  with 

coiumonsalt. 

IV. 

Nitrate  of 
potash. 

V. 

Nitrate  of 
potash  with 
commonsalt. 

VI. 

Guano. 

1857. 
Summer-barley. 
Quantity   of    ma- 

kilos. 

kilos. 
402 

kilos. 
402  +  1379 

kilos. 
473 

kiloe. 
473  +  1379 

kilos. 
473 

.  (  Corn  

(Straw.     .     .. 

1604 
2580 

2676 
4378 

2366 
4352 

2064 
4219 

2313 
4766 

1922 
3300 

1858. 

Winter-  wheat, 
(the  same 
manures.) 

T>  (  Corn    . 

1699 

1804 

2211 

2248 

2323 

2366 

**  \  Straw 

3030 

3954 

4151 

4404 

4454 

5091 

The  experiments  are  remarkable  in  so  far  as  they 
appear  to  indicate  the  cases  in  which  the  nitrates  alone, 


EFFECT   OF   COMMON    SALT.  319 

or  in  combination  with  common  salt,  exert  a  favourable 
influence  upon  the  increase  of  the  crops. 

The  land  in  Weihenstephan  is  peculiarly  suited  for 
the  cultivation  of  barley.  Field  A,  after  a  manuring 
of  the  ordinary  kind,  about  600  cwt.  per  hectare,  had 
borne  turnips  in  1854,  peas  in  1855,  and  wheat  in  1856 ; 
it  was  then  intended  to  let  it  lie  fallow  for  one  year, 
and  to  dress  it  at  the  end.  of  the  year  for  a  new  crop. 
On  the  other  hand,  Field  B,  before  the  experiment  was 
made,  had  already  borne  four  crops,  namely,  rape, 
wheat,  clover  grass,  and  oats  ;  and  was,  in  comparison 
with  the  first  field,  more  exhausted,  and  by  means  of 
the  oats  and  clover  made  much  poorer  in  nutritive  sub- 
stances for  the  following  cereal  crop. 

This  seems  to  afford  an  explanation  of  the  striking 
fact,  that  in  185T  the  nitrates  exercised  upon  the  field 
a  far  more  favourable  influence  than  guano,  although 
the  soil  had  received  as  much  nitrogen  in  the  guano  as 
in  the  nitrates,  with  the  addition  of  phosphoric  acid 
and  potash.  The  field  was  still  rich  enough  in  nutri- 
tive substances  for  a  good  barley  crop,  and  merely 
required  their  more  uniform  distribution  (which  was 
effected  by  the  nitrates  and  the  common  salt),  in  order 
to  make  available  to  the  roots  of  the  barley  plants  as 
much  or  even  more  food  than  was  the  case  with  the 
plot  manured  with  guano,  on  which  the  sum  of  the  nutri- 
tive substances  was  greater. 

In  estimating  the  results  of  these  experiments  we 
must  take  into  account  the  fact  established  by  Dr. 
Zoeller,  that  soda  seems  to  take  a  definite  part  in  the 
production  of  barley  seed.  It  is  clear  that  the  nitrates 
used  did  not  simply  act  as  agents  in  distributing  other 
nutritive  substances,  but  the  soda  as  well  as  the  nitric 
acid  had  their  own  share  in  the  production  of  the  crop. 
In  the  fourth  experiment  the  field  received  as  much 
nitric  acid  as  in  the  second,  but  the  base  combined 
with  the  acid  was  potash  and  not  soda ;  and  in  the 
fifth  experiment  the  addition  of  common  salt  produced 
a  remarkable  increase  in  the  corn  crop.  However,  in 
the  third  and  fifth  experiments  the  quantity  of  salt  ap- 


320      SALT,    NITRATE    OF   SODA,    SALTS    OF   AMMONIA,    ETC. 

plied  was  evidently  too  high,  and  the  excess  brought 
down  the  crop  below  that  obtained  with  nitrate  of  soda 
alone. 

Upon  the  more  exhausted  field  in  1858  the  crop 
obtained  by  guano  in  corn  and  especially  in  straw  ex- 
ceeded all  the  rest.  In  the  arable  soil  of  this  field  the 
amount  of  nutritive  substances  was  on  the  whole  smaller, 
and  the  addition  of  fresh  elements  of  food  made  itself 
felt  in  a  much  higher  degree  than  the  distribution  or 
dissemination  of  the  substances  already  present  in  the 
soil.  Still  by  the  addition  of  common  salt  the  crop  of 
wheat  was  also  increased. 

The  effect  of  potash  upon  wheat  is  as  striking  as 
that  of  soda  upon  barley. 

As  regards  the  effect  of  common  salt  and  salts  of 
soda  generally,  the  analysis  of  the  ash  of  turnips  and 
potatoes,  kitchen -garden  and  meadow  plants,  shows 
that,  as  a  rule,  the  ashes  of  the  former  contain  a  con- 
siderable quantity  of  soda,  and  the  ashes  of  the  latter 
are  proportionately  rich  in  chlorides.  The  grass  of  a 
meadow,  which  has  been  manured  with  common  salt, 
is  eaten  by  cattle  with  greater  relish,  and  preferred  to 
any  other,  so  that  even  from  this  point  of  view  com- 
mon salt  deserves  attention  as  a  manure. 

As  that  part  of  the  action  of  nitrate  of  soda,  sea-salt, 
and  salts  of  ammonia,  which  consists  in  effecting  the 
distribution  in  the  soil  of  other  elements  of  food,  may 
consequently  be  replaced  by  careful  tillage,  the  effect 
produced  upon  the  crops  by  these  salts  affords  a  pretty 
safe  indication  of  the  condition  of  a  field.  If  all  other 
circumstances  are  the  same,  their  effect  will  be  much 
less  marked  upon  a  w^ell  tilled  field  than  upon  one  not 
in  the  same  condition. 

Gypsum. — Among  the  recent  investigations  respect- 
ing the  action  of  gypsum  on  clover,*  those  made  by  Dr. 

*  That    excellent    and    most    ably  conducted    agricultural   journal, 
4  Zeitschrift  des  landwirthschaftlichen  Vereins  fiir  Rhein.  Preussen,'  con- 
tains, in  Nos.  9  and  10,  September  and  October  1861,  p.  352,  the  follow- 
ing statement  about  the  remarkable  fertility  of  a  field  for  clover : — 

*  Twenty-three  years  ago  Farmer  Kirfield,  of  Rhon,  in  the  hundred  of 


ACTION   OF   GYPSUM   ON   CLOVEK.  321 

Pincus,  of  Insterburg,  are  the  most  important,  both,  on 
account  of  the  careful  manner  in  which  they  were  con- 
ducted, and  the  conclusions  drawn  from  them.  At  Dr. 
Pincus'  request,  three  plots  of  ground,  each  of  a  morgen 
(about  f  of.  an  acre)  in  extent,  and  lying  close  together, 
were  selected  by  Mr.  Eosenfeld  in  the  beginning  of 
May,  from  the  middle  of  a  large  clover  Held  in  the 
neighbourhood  of  Lenkeningken.  The  clover  crop  had 
a  very  promising  appearance,  and  the  plants  were  then 
about  an  inch  high.  One  of  the  plots  was  manured 
with  a  cwt.  of  gypsum,  the  second  with  the  same  quan- 
tity of  sulphate  of  magnesia,  and  the  intervening  plant 
was  left  unmanured.  The  clover  field  from  which  the 
plots  were  selected  was  one  of  the  best  cultivated  and 
most  fertile  in  the  district,  and  had  produced  in  the 
preceding  summer  an  abundant  rye  crop.  The  plants 
growing  on  the  unmanured  plot,  when  compared  with 
those  on  the  manured,  very  speedily  presented  a  differ- 
ence of  colour  and  condition. 

On  the  plot  manured  with  gypsum,  they  were  of  a 
deeper  green,  and  stood  higher.  The  difference  was 
most  striking  at  the  time  of  flowering,  which  occurred 
in  the  unmanured  plots  four  or  five  days  earlier  than 
in  the  manured ;  the  whole  field  being  everywhere  in 
full  bloom,  when  scarcely  a  flower  was  to  be  seen  in 
the  manured  plots.  When  the  manured  plots  also  were 

Antweiler,  Aldenau  district  (volcanic  Eifel  mountains),  sowed  a  plot  of 
land,  said  to  abound  in  broken  shells,  with  esparsette.  For  ten  years  he 
obtained  good  hay  crops,  and  abundant  after-grass.  After  this  time  a  good 
deal  of  grass  began  to  make  its  appearance  among  the  esparsette.  To 
destroy  this  Mr.  Kirfield  had  his  field  deeply  harrowed  in  spring,  with  iron 
harrows  across  the  ridges,  and  then  sown  over  again  with  8  pounds  of  red 
clover  seed.  The  red  clover  grew  up  splendidly  with  the  esparsette,  and 
gave  for  three  years  running  two  full  crops  per  annum.  At  the  end  of  the 
third  year  the  land  was  again  deeply  harrowed  and  sown  anew  with  8 
pounds  of  red  clover  seed.  It  gave  again  for  three  years  running  two  full 
crops  per  annum  of  an  excellent  mixture  of  esparsette  and  red  clover. 
The  same  operation  was  repeated  twice  after  with  the  same  success,  so 
that  the  field  has  now  for  twenty-two  years,  consecutively,  borne  clover ; 
that  is  to  say,  the  first  ten  years  esparsette  alone,  the  following  twelve 
years  esparsette  with  red  clover.' 

It  would  be  interesting  to  get  a  proper  analysis  of  this  soil,  with  especial 
regard  to  its  absorptive  power  for  potash  and  phosphate  of  lime. 
14* 


322 

in  flower  the  clover  was  mown  (May  24th).  A  square 
ruthe  was  measured  from  each  of  the  experimental  plots, 
and  the  clover  separately  cut  and  weighed. 

Calculated  per  Prussian  morgen  (  —  -f  of  an  acre), 
the  results  were, — 

Cwts.  of  clover-hay 
per  morgen . 

Without  manure 21-6  cwts. 

With  gypsum 30*6     " 

With  sulphate  of  magnesia 32'4     '« 

On  a  closer  examination  of  the  clover-hay  it  was 
found  that  the  increase  in  the  crops  obtained  from  the 
plots  manured  with  the  sulphates  did  not  extend  equally 
to  all  parts  of  the  plant,  but  was  more  particularly  ob- 
servable in  the  production  of  stems.  There  were  found 
in  100  parts  of  the  clover  from  the  manured  plots  more 
stems,  fewer  leaves,  and  still  fewer  flowers,  than  in  100 
parts  of  the  unmanured  clover. 

Manured    Manured 
Unmanured.      with    with  sulphate 
gypsum,  of  magnesia. 

100  parts  of  clover-hay,  flowers 17'15        11-72        12-16 

"  leaves  27'45         26-22         25-28 

stems 55-40         61'62         63'0 

or, 

Flowers.  Leaves.  Stems. 

Clover-hay,  unmanured 17-15  27-45  55-40 

"         manured  with  gypsum        11*72  25-28  63'0 
"                "            sulphate  of 

magnesia 12-16  26-22  61-62 

These  proportions  of  the  different  organs  of  the 
clover  plant  show  that  the  action  of  the  sulphates  has 
led  to  a  very  considerable  increase  of  the  wood-cells, 
or,  in  other  words,  to  an  extension  of  the  stems  at  the 
expense  of  the  flowers  and  leaves.  The  relative  propor- 
tion of  the  flowers,  leaves,  and  stems,  was  : — 

Flowers.  Leaves.          Stemp. 

Clover-hay,  unmanured  100      :       160  :       323 

"        manured  with  gypsum        100      :       216  :       507 
"                "              sulphate  of 

magnesia 100      :       216  :       538 

According  to  the  law  of  the  symmetrical  develope- 
ment  of  plants,  we  may,  without  risk  of  error,  take  it 


EFFECT  OF  GYPSUM  ON  CLOVEK.         323 

for  granted  that  the  developement  of  the  root  increased 
in  the  same  ratio  as  that  of  the  stem.  Now,  as  the  in- 
crease of  a  plant'  in  bulk  is  proportionate  to  the  extent 
of  food  absorbent  surface,  we  can  understand  that  the 
manured  plots  should  have  produced  when  compared 
with  the  unmanured  not  only  a  larger  mass  of  stems, 
but,  as  in  the  case  of  the  sulphate  of  magnesia  plot, 
also  of  flowers  and 'leaves. 

The  entire  crop  per  morgen,  was, — 

Manured  Manured  with 
.  Unmanured.            with  sulphate  of 

gypsum.  magnesia. 

Flowers 370-5  Ibs.        358-5  Ibs.         394-0  Ibs. 

Leaves 592-9    "  773-7     "          849-5  " 

Stems  1196-6    •'         1927'8     "        1996'5  " 

2160       "          3060       "         3240      " 

The  quantity  of  most  of  the  ash  constituents  was 
found  larger,  nearly  in  the  same  proportion  as  the  pro- 
duce was  greater.  Phosphoric  and  sulphuric  acids, 
however,  showed  in  this  respect  a  marked  difference 
from  the  other  ash-constituents,  inasmuch  as  the  quan- 
tity of  these  two  substances  was  both  absolutely  and 
relatively  larger  in  the  clover  from  the  manured  plots. 

The  ash  of  the  air-dried  clover-hay  amounted  to — 

Manured  Manured  with 

Unmanured.             with  sulphate  of 

gypsum.  magnesia. 

Percent 6'95                  7'96  7'94 

In  the  entire  crop  150'0  Ibs.         243'0  Ibs.  257 '0  Ibs. 

Containing  sulphuric  acid 2-0    "               8'0    "  6'0    " 

phosphoric  acid  ...       11-95  "             21-55  "  21-82  " 

The  dressing  with  the  sulphates  had  checked  the 
developement  of  the  flowers,  and  also  that  of  the  fruit ; 
and  it  is  evident  that,  though  a  higher  crop  of  stems 
and  leaves  may  be  obtained  by  the  use  of  these  agents 
from  a  given  surface,  the  result  is  not  the  same  as  re- 
gards the  seeds.  With  an  increase  of  flowers,  leaves, 
and  stems  in  the  same  ratio  as  on  the  unmanured  plot, 
the  two  morgens  of  ground,  dressed  severally  with 
gypsum  and  sulphate  of  magnesia,  ought  to  have  pro- 
duced more  than  600  Ibs.  of  flowers  each  ;  whereas, 


324:     SALT,    NITRATE   OF   SODA,    SALTS   OF  AMMONIA,   ETC. 

compared  with  the  enormous  increase  in  the  weight  of 
the  stems,  and  a  not  inconsiderable  one  in  the  weight 
of  the  leaves,  we  find  no  increase  of  flowers,  and  con- 
sequently also  none  of  seed  (Pincus).  These  most  care- 
fully conducted  experiments  confirm  the  general  rule, 
that  wherever  external  causes  favour  the  developement 
of  some  organs,  it  can  only  be  eifected  under  like  con- 
ditions of  the  soil,  at  the  expense  of  other  organs,  and 
that  in  the  case  of  clover,  as  in  that  of  the  cereals,  in- 
crease of  straw  is  attended  with  decrease  of  seed.  (For 
further  details  of  these  experiments,  see  Appendix  J.) 

As  the  substitution  of  magnesia  for  lime,  in  the  ex- 
periments now  described,  led  to  an  increase  of  the 
clover  crop,  it  may  be  safely  assumed  that  in  cases 
where  gypsum  is  found  to  be  favourable  to  the  growth 
of  clover,  the  cause  must  not  be  sought  for  in  the  lime, 
although  it  is  very  often  found  that  many  fields  will 
grow  clover  only  after  a  copious  dressing  with  hydrate 
of  lime.  For  we  know  also  that  gypsum  promotes  the 
growth  of  clover  on  many  fields  naturally  abundant  in 
lime  ;  and  since  arable  soil  has  the  property  of  absorb- 
ing ammonia  from  the  air  and  rain-water,  and  fixing  it 
in  the  same  or  even  a  higher  degree  than  salts  of  lime, 
there  is  only  the  sulphuric  acid  left  to  look  to  for  an 
explanation  of  the  favourable  action  of  gypsum  upon 
the  growth  of  clover. 

But  the  experiments  of  Pincus  clearly  demonstrate 
that  the  crops  obtained  by  manuring  with*  the  sulphates 
bear  no  proportion  whatever  to  the  quantity  of  sul- 
phuric acid  supplied  in  them  to  the  field. 

The  quantities  of  sulphuric  acid  severally  contained 
in  the  two  sulphates  used  were  30*12  Ibs.  in  the  sul- 
phate of  magnesia,  and  44*18  Ibs.  in  the  sulphate  of 
lime,  which  is  as  6  :  8*8.  The  quantities  of  sulphuric 
acid  in  the  two  crops  obtained  severally  by  sulphate 
of  lime  and  sulphate  of  magnesia,  were  as  6  :  8  ;  the 
ash  of  the  clover  produced  by  sulphate  of  lime  con- 
tained a  little  more  than  8  Ibs.,  and  that  from  the  sul- 
phate of  magnesia  6  Ibs.  On  the  plot  dressed  with 
gypsum  the  clov*er  plant  found  a  larger  total  quantity 


ACTION   OF   GYPSUM   ON   CLOVER   NOT   KNOWN.        325 

of  sulphuric  acid  than  on  the  sulphate  of  magnesia  plot, 
and  absorbed  a  correspondingly  larger  proportion.  But 
this  additional  quantity  of  sulphuric  acid  absorbed  did 
not  increase  the  amount  of  produce ;  on  the  contrary, 
on  the  plot  manured  with  sulphate  of  magnesia,  which 
had  received  less  sulphuric  acid  than  the  gypsum  plot, 
the  amount  of  vegetable  matter  was  8  per  cent,  higher 
than  on  the  latter. 

These  facts  show  that  we  are  still  in  the  dark  about 
the  action  of  gypsum ;  and  it  will  yet  require  a  great 
many  and  most  accurate  observations  before  we  are 
likely  to  arrive  at  a  satisfactory  explanation. 

So  long  as  the  notion  was  generally  entertained  that 
plants  derived  their  food  from  a  solution,  the  effects  of 
a  soluble  salt  upon  vegetation  could,  of  course,  be  at- 
tributed only  to  the  constituents  of  that  salt.  But  now 
we  are  aware  that  the  earth  itself  performs  a  special  part 
in  all  the  processes  of  nutrition ;  and  there  might,  there- 
fore, be  grounds  for  supposing  that  the  action  of  gypsum 
upon  arable  earth,  or  of  the  latter  upon  the  former, 
might  furnish  a  key,  to  some  degree  at  least,  to  explain 
the"  effect  of  gypsum  upon  the  growth  of  clover.  A 
series  of  experiments  made  by  me  upon  the  alterations 
which  a  saturated  solution  of  gypsum  in  water  under- 
goes in  contact  with  different  arable  soils,  give  very 
remarkable  results,  whch  I  will  now  state,  without 
venturing  to  draw  any  definite  conclusions  from  them. 

I  found  that  a  solution  of  gypsum  in  contact  with 
all  the  arable  soils  which  I  used,  underwent  decompo- 
sition, part  of  the  lime  separating  from  the  sulphuric 
acid,  and  magnesia  and  potash  taking  its  place,  quite 
contrary  to  the  ordinary  affinities. 

The  experiments  were  made  as  follows : — 300 
grammes  of  each  earth  were  mixed  with  a  litre  of  pure 
water,  and  300  other  grammes  of  the  same  earth  with 
a  litre  of  a  saturated  solution  of  gypsum.  After  twenty- 
four  hours  the  fluid  was  filtered,  and  the  filtrate  tested 
for  magnesia.  Pure  distilled  water  took  up  from  all 
the  experimental  earths,  sulphuric  acid  and  chlorine, 
besides  traces  of  lime,  magnesia,  and  soda,  and  occa- 


326      SALT,    NITRATE   OF    SODA,    SALTS   OF   AMMONIA,    ETC. 

sionally  also  of  potash,  but  mostly  in  inappreciable 
quantities.  The  alkalies,  as  well  as  the  lime  and  the 
magnesia,  seem  to  be  dissolved  by  the  agency  of  or- 
ganic matters,  as  the  dried  residues  blackened  upon 
heating,  and  effervesced  with  acids  after  ignition. 

Quantities  of  magnesia  dissolved  severally  out  of  300  grammes 
of  earth  by  one  litre  of 

Distilled  water.  Gypsum  water. 

Milligr.  of  magnesia.    Milligr.  of  magnesia. 

Bogenhausen  earth 3O2  70'6 

Schleissheim     "       31'6  878 

Bogenhausen  subsoil  12*2  84'2 

Earth  from  Botanic  Gardens 45-4  168-6 

"          Bogenhausen,  No.  L*  26'6  101 '6 

"                     "             No.  II.  38-2  98-0 

Schornhof 8'6  634 

a  cotton  field,  Alabama  1-9  3 '8 

These  figures  show  that  dressing  a  field  with  sul- 
phate of  lime  makes  the  magnesia  in  the  soil  soluble 
and  distributable.  If  the  action  which  gypsum  exer- 
cises upon  the  growth  of  clover  depends  really  upon 
an  increased  supply  of  magnesia,  this  must  surely  be 
looked  upon  as  one  of  the  most  curious  facts  known, 
since  the  increased  supply  is  effected  here  by  the  aid 
of  a  lime  salt.  An  experiment,  made  specially  for  the 
purpose,  showed  that  the  contact  of  arable  earth  with 
the  solution  of  sulphate  of  lime  is  attended  by  an  actual 
substitution  of  magnesia  for  lime  ;  that  is  to  say,  a  cer- 
tain quality  of  lime  is  withdrawn  from  the  solution  and 
combines  with  the  earth,  whilst  the  liberated  sulphuric 
acid,  which  was  united  to  the  lime,  withdraws  from  the 
earth  an  equivalent  quantity  of  magnesia.  In  a  litre 
of  gypsum  water  which  had  been  in  contact  with  300 
grammes  of  earth  from  a  wheat-field,  there  were  found 
the  following  quantities  of  sulphuric  acid,  magnesia,  and 
lime : — 

*  On  this  field  it  had  been  experimentally  proved  that  dressing  Avith 
gypsum  would  give  a  larger  clover  crop.  No.  I.  had  not  yet  been  manured 
Avith  gypsum,  No.  II.  had. 


THE   ACTION    OF   GYPSUM   IS    COMPLEX.  327 

The  pure  gypsum  The  gypsum  water  which 

water  had  been  in  contact 
contained  in  1  litre—  with  the  earth- 
Sulphuric  acid 1-1 70  grammes.  1-180  grammes. 

Lime 0'820        "  0-736 

Magnesia —  0-074 

Besides  the  magnesia,  a  certain  amount  of  potash  also 
seems  to  be  dissolved  out  of  the  earth  by  aid  of  the 
oypsum. 

Out  of  1000  grammes  of  earth  from  a  wheat-field, 
there  was  dissolved  by — 

3  litres  of  pure  water.    3  litres  of  gypsum- water. 
Potash 24-3  milligr.  43 '6  milligr. 

These  experiments  show  that  the  action  of  gypsum 
is  very  complex,  and  that  it  promotes  the  distribution 
of  both  magnesia  and  potash  in  the  ground.  This  much 
is  certain,  that  gypsum  exercises  a  chemical  action  upon 
the  soil,  which  extends  to  any  depth  of  it,  and  that  in 
consequence  of  the  chemical  and  mechanical  modifica- 
tion of  the  earth  particles  of  certain  nutritive  elements 
become  accessible  to,  and  available  for,  the  clover  plant, 
which  were  not  so  before. 

The  cause  of  the  action  of  a  manuring  agent  is  usually 
sought  for  in  the  composition  of  the  plant,  but  I  do  not 
think  that  this  is  always  to  be  relied  upon.  The  compo- 
sition of  the  seed  of  plants  of  wheat,  for  instance,  is  so 
constant,  or  varies  so  little,  that  it  is  quite  impossible 
to  infer  from  the  results  of  the  analysis  of  the  seeds 
whether  the  soil  on  which  they  grow  abounded  or  was 
deficient  in  phosphoric  acid,  nitrogen,  potash,  &c.  The 
abundance  or  deficiency  of  food  in  a  field  exercises  an 
influence  upon  the  number  and  weight  of  the  seeds, 
but  not  upon  the  relative  proportion  of  their  compo- 
nent elements.  Thus,  for  instance,  Pincus  found  a  some- 
what larger  percentage  of  magnesia  in  the  unmanured 
clover  than  in  the  plants  manured  with  the  sulphates  ; 
but  taking  the  magnesia  of  the  whole  crop,  the  quantity 
of  this  substance  was  much  larger  in  the  latter  than  in 
the  former. 


328     SALT,   NITKATE   OF   SODA,    SALTS   OF  AMMONIA,   ETC. 

Amount  of  magnesia  in — 

Manured  Manured 

Unmanurcd.  with  with  sulphate 

gypsum.  of  magnesia. 

100  parts  of  ash  of  clover-hay  5'S7  5*47  5'27 

In  the  whole  crop  ,.     8-8  Ibs.         13'29  Ibs.        13'54'lbs. 

Yariations  in  the  percentage  proportions  of  potash, 
lime,  and  magnesia,  may  be  often  observed  in  all  those 
plants  in  which,  as  in  the  case  of  tobacco,  the  vine,  and 
the  clover  plant,  potash  may  be  substituted  for  lime, 
and  vice  versa.  But  in  such  cases  the  decrease  of  one 
body  is  invariably  attended  by  a  corresponding  increase 
of  the  other. 

Now  if  gypsum  has  the  property  of  effecting  a  dis- 
tribution of  the  potash  in  the  ground,  and  this  is  want- 
ing in  magnesia,  more  potash  should  be  contained  in 
the  clover  manured  with  gypsum  than  with  sulphate 
of  magnesia.  According  to  the  analysis  made  by 
Pincus,  the  ash  of  the  clover-hay  contained  : — 


In  per  cent 

In  the  whole  ash 


Clover  Clover  manured 

manured  with  with  sulphate 

gypsum.  of  magnesia. 

Potash 35-37  Ibs.  32'91  Ibs. 

Lime    19'17    "  20-66    " 

Potash 85-9      "  84'6      " 

Lime 46-6      '  53'2      " 


These  figures  show  that  the  quantity  of  potash  is 
indeed  larger,  and  that  of  lime  smaller,  in  the  crop 
produced  by  manuring  with  sulphate  of  lime  than  in 
the  higher  crop  from  sulphate  of  magnesia. 

In  the  clover-hay  reaped  from  the  latter  plot,  the 
deficient  potash  was  manifestly  replaced  by  lime,  and 
in  the  clover-hay  from  the  gypsum  manure  plot,  a  cer- 
tain amount  of  lime  by  potash. 

An  investigation,  made  with  much  carefulness,  and 
without  the  least  bias,  as  this  by  Pincus,  appears, 
among  the  frivolous  and  loosely-conducted  researches 
with  which  agriculture  unfortunately  abounds,  like  a 
green  oasis  in  a  dreary  desert,  and  is  well  calculated 
to  show  how  much  real  knowledge  remains  still  to  be 
gained  of  the  processes  in  the  soil  with  respect  to  the 
nutrition  of  plants.  (See  '  Agriculturo-chemical  and 


ACTION   OF  LIME.  329 

Chemical  Researches  and  Experiments  made  by  Dr. 
Pincus,  at  the  Insterburg  Station  for  Agriculturo- 
chemical  and  Physical  Experiments.'  Gumbinnen. 
1861.) 

Lime. — I  have,  unfortunately,  never  had  an  oppor- 
tunity of  examining  a  soil  on  which  a  lime-dressing 
has  exercised  a  beneficial  effect,  as  this  substance  is  not 
used  by  farmers  in  the  neighbourhood  either  of  Giessen 
or  of  Munich.  The  experiments  made  by  Kuhlmann, 
on  meadows,  in  the  years  1845  and  1846,  seem  to  show 
that  lime  is  principally  useful  in  altering  the  condition 
of  the  soil ;  but  having  no  data  before  me  as  to  the  par- 
ticular soil  on  which  these  experiments  were  made,  I 
am  unable  to  point  out  wherein  this  alteration  consists. 

Hay  crop  reaped  per  hectare,  1845  and  1846. 

kilos.  kilos. 

Meadow  unmanured 11253  — 

"       manured  with  300  kilos,  of  slaked 

lime,  each  year  14263  Increase  3000 

"      manured  with  500  kilos,  of  chalk 

each  year 10706  Decrease    556 

It  may  safely  be  taken  for  granted  here,  that  if  the 
lime  had  acted  as  a  nutritive  element  in  the  develope- 
ment  of  the  meadow  plants,  the  plot  manured  with 
carbonate  of  lime  ought  to  have  given  a  higher,  but 
assuredly  in  no  case  an  inferior  crop,  than  the  unma- 
nured plot.  But  the  very  reverse  is  the  case  :  the  car- 
bonate of  lime,  which  could  only  spread  through  the 
soil  dissolved  in  carbonic  acid,  had  an  unfavourable 
effect ;  the  caustic  lime,  on  the  contrary,  was  beneficial. 

Among  the  Saxon  experiments  already  so  often 
alluded  to,  there  are  two  of  sufficient  importance  to 
deserve  particular  mention  here.  One  of  these  was 
made  by  Traeger,  of  Oberbobritzsch ;  the  other  by 
Trager,  of  Friedersdorf.  The  latter  omitted  to  make 
a  comparative  experiment  to  show  the  difference  be- 
tween the  produce  from  a  plot  manured  with  lime,  and 
that  from  an  unmanured  plot  of  the  same  size.  Instead 
of  the  latter,  therefore,  I  placed  here  by  the  side  of  the 


330      SALT,    NITRATE   OF   SODA,    SALTS   OF   AMMONIA,    ETC. 

lime  experiment,  for  the  sake  of  comparison,  another 
made  with  ground  bones  on  a  plot  of  the  same  size. 

Experiment  at  Oberbobritzsch. 
Lime  manuring  (110  cwts.  quick  lime). 


Produce  per  acre, 
unmanured. 

A 

Produce  per  acre, 
manured  with  lime. 

Corn. 

Straw. 

Corn. 

Straw. 

1851.  Rye  

Ibs. 
1453 
1528 
9751 
911 

Ibs. 
3015 
1812 

Ibs. 
1812 
1748    * 
11021 
2942 

Ibs. 
3773 
2320 

1853    Oats    . 

1852.  Potatoes  .  . 
1854.  Clover-hay. 

Experiment  at  Friedersdorf. 
Lime  manuring  (same  quantity  as  above). 


Produce  per  acre,  manured 
with  1644  Ibs.  ground  boues. 

Produce  per  acre, 
manured  with  lime. 

Corn. 

Straw. 

Corn. 

Straw. 

1851.  Rye  .    .    . 

Ibs. 
990 
1250 
8994 
4614 

Ibs. 
3273 
2226 

Ibs. 
1012 
1352 
12357 
4438 

Ibs. 
3188 
2280 

1853.  Oats  

1852.  Potatoes  .  . 
1854.  Clover-hay. 

Guano  produced,  in  the  year  1854,  on  the  field  at 
Oberbobritzsch,  a  higher  clover  crop  than  the  lime  (see 
page  266) ;  but  on  the  field  at  Friedersdorf  it  was 
smaller,  616  Ibs.  of  guano  produced,  at  Friedersdorf, 
2337  Ibs.,  at  Oberbobritzseh,  5044  Ibs.,  of  clover-hay. 

Experiments,  in  which  I  brought  lime-water  in  con- 
tact with  different  samples  of  arable  soil,  have  shown 
that  the  latter  possesses  a  similar  absorptive  power  for 
lime  as  for  potash  and  ammonia.  The  earth  was  mixed 
with  lime-water,  and  after  remaining  at  rest  until  all 
alkaline  reaction  had  disappeared,  a  fresh  quantity  of 
lime-water  was  then  added,  just  sufficient  to  cause  a 
feeble  but  permanent  alkaline  reaction. 


EXPERIMENTS   WITH   LIME. 


331 


Experiments  on  the  amount  of  lime  taken  up  out  of  lime-watev 
by  different  arable  soils. 


Lime  out  of 

lime-water. 

1  litre*  of  Bogenhausen  earth  took  up 
1                 Schleissheim  earth     .    • 

grms.    grains. 
2-824=43-5 
2-397—37-0 

grms.  grains. 
2259=34788 
1917  —  29521 

1                 earth  from  Botanic  Gardens 
1                subsoil  from  Bogenhausen  . 
1                 wheat  soil  

3-000=46-2 
3-288  =  50-6 
2-471—38*0 

2400=36960 
2630=40502 
1976—30430 

*  1           from  the  same  field  after  bearing 
a  crop  of  clover                 . 

2-471—38*0 

1976—30430 

1     "     of  turf  powder  

6-301  —  97-0 

5040—77616 

The  investigation  into  the  alterations  produced  in 
the  earth  by  the  absorption  of  lime,  more  especially  as 
regards  potash  and  silicic  acid  rendered  soluble,  is  not 
yet  terminated. 

*  1  Litre  =  1  cubic  decimetre  =  61  cubic  inches. 


APPENDICES. 


APPENDIX  A   (page  S3). 

EXAMINATION    OF   BEECH-LEAVES   AT   DIFFERENT   STAGES    OF 
GROWTH.       (DR.  ZOELLER.) 

Beech  leaves  and  asparagus,  their  ash-constituents  at  different  periods  of  growth — 
The  amylum  of  the  palm— Motion  of  sap  in  plants— Drain,  lysimeter,  river,  and 
bog  water,  their  constituents— Fontinalis  antipyretica  from  two  different  waters, 
ash-constituents— Vegetation  of  maize  in  solutions  of  its  food — Experiments  on 
the  growth  of  beans  in  pure  and  prepared  turf,  results— Japanese  agriculture — 
The  cultivated  soil  of  the  torrid  zone,  its  exhaustibility,  its  manure— Analysis 
of  clover  by  Pincus— Clover  sickness,  its  cause 

THE  beech  tree  (fagus  sylvatica),  from  which  the  leaves  ex- 
amined were  gathered,  stands  in  the  Botanical  Garden  of 
Munich.  The  leaves  marked  I.  period  were  taken  from  the  tree 
of  four  different  sizes,  on  May  16,  1861.  The  smallest  leaves  a 
were  just  unfolded  from  the  leaf-bud,  whilst  those  marked  d  were 
fully  expanded.  There  were  between  a  and  d  a  difference  of  four 
days'  growth.  The  other  two  sets,  marked  severally  5  and  c,  were 
in  size  and  period  of  growth  intermediate  between  a  and  d.  The 
leaves  of  the  I.  period  were  very  delicate,  and  of  yellowish  green 
colour. 

The  leaves  of  the  II.  period  were  gathered  on  July  18,  those 
of  the  III.  period  on  October  15,  1861.  The  leaves  of  each  period 
possessed  among  themselves  the  same  size  and  firmness  of  structure. 
The  colour  of  the  July  leaves  was  dark  green,  of  those  of  October 
somewhat  lighter. 

The  leaves  of  the  IV.  period  were  from  the  same  tree,  but  had 
been  gathered  in  the  end  of  November,  1860.  They  had  withered 
on  the  tree,  and  were  quite  dry. 


EXAMINATION   OF   BEECH-LEAVES. 


333 


One  hundred  parts  by  weight  of  the  fresh  beech  leaves  con- 
tained : — 

I.  Period.  II.          III. 

< • >    Period.   Period. 


Dry  substance*. 
Water  . . 


a 

30-29 
69-71 


22-04: 
77-96 


c 

21-53 

78-47 


d 
21-52 

78-46 


44-13 
55-87 


43-23 

56-77 


One  thousand  fresh  leaves  contained,  in  grammes : — 


Dry  substance 10-01 

Water 22-61 

Total  weight  of  1000  leaves. .  32-62 

Ash  of  dry  leaves  per  cent. . .  4'65 


15-90      32-63       60-00     116-16     117'53 
57-26    118-91    218-31    147'04    154'33 


73-16    151-54    278-31    263-20    271'86 
5-40        5-82        5-76        7'57      10'15 


The  amount  of  water  in  the  air-dried  leaves  of  the  IV.  period 
was  11-89  per  cent.  The  quantity  of  ash  left  by  the  dried  leaves 
was  8-TO  per  cent. 

For  the  ash  analysis  of  the  leaves  of  the  period  I.,  an  equal 
number  of  leaves  &,  e,  d,  were  incinerated. 

One  hundred  parts  of  the  ash  of  the  leaves  contained: — 


I.  Period. 
16th  May, 
1861. 

II.  Period. 
18th  July, 
1861. 

III.  Period. 
14th  October, 
1861. 

IV.  Period. 
End  of  Nov., 
1860. 

Soda  

2-30 

2-34 

1-01 

# 

Potash           .         .... 

29*95 

10-72 

4-85 

0'99 

Magnesia               . 

3-10 

3-52 

2-79 

7-13 

Lime 

9-83 

26-46 

34-05 

34*13 

Sesquioxide  of  iron  
Phosphoric  acid         .   .  . 

0-59 
24-21 

0-91 
5-18 

0-94 
3-48 

1-10 
1-95 

Sulphuric  acid       .    .   . 

* 

* 

* 

4-98 

Silicic  acid 

1*19 

13"37 

20-68 

24-37 

Carbonic  acid  and  con-  } 
stituents  not  deter-  >• 
mined  .        ) 

28-83 

37-50 

32-20 

25-35 

Total  

100-00 

100-00 

100*00 

100-00 

*  Not  determined. 


334 


APPENDIX  A. 


Analysis  of  the  ash  of  the  leaves  of  the  fiorse-chestnut  and  the  walnut-tree, 
by  E.  STAFFEL.     (lAn.  der  Chem.  und  PJiarm.J  vol.  Ixxvi.  p.  372.) 


Horse-chestnut. 

Walnut-tree. 

Spring. 

Autumn. 

Spring. 

Autumn. 

Moisture  in  100  parts  ) 
of  fresh   substance,  V 
dried  at  212°  Fahr...  ) 
Per  cents  of  ash  in  the  ) 
fresh  substance  J 
Per  cents  of  ash  in  the  ) 
dried  substance  j 

100  parts  of  ash  con- 
tained — 

82'09 

1-376 
7-69 

56-27 

3-288 
7-52 

82-15 

1-092 

7-719 

63-31 

2-570 
7-005 

46-38 
13-17 
5-15 
0-41 
1-63 
2-45 
1-76 
24-40 
4-65 

14-17 
40-48 
7-78 
0-51 
4-69 
1-69 
13-91 
8-22 
8-55 

42-04 
26-86 
4'55 
0-18 
0-42 
2-58     . 
1-21 
21-12 
1-04 

25-48 
53-65 
9-83 
0-06 
0-52 
2-65 
2'02 
4-04 
1-73 

Sesquioxide  of  iron  
Sulphuric  acid       .       .  . 

Silicic  acid               

Phosphoric  acid       

Chloride  of  potassium.  .  . 
Total  

100-00 

100-00 

100-00 

99-98 

Analysis  of  the  ash  of  flowering  asparagus  shoots,  and  of  withered  shoots 
with  ripe  fruit.— DR.  ZOELLER. 


I. 

Flowering 
shoots. 

II. 

Autumn  shoots 
with  ripe  fruit. 

Moisture  in  100  parts  of  the  fresh  substance,  ) 
dried  at  212°  Fahr                                       .  .  .  J 

84-34 

59-23 

Per  cents  of  ash  of  the  fresh  substance        

0-946 

4-13 

Per  cents  of  ash  of  the  dried  substance  

6-050 

10-13 

100  parts  of  ash,  contain  — 

5-11 

5-25 

Potash 

34'40 

11-77 

4-69 

3-61 

Lime                                    ,                

9'07 

24-05 

Sesquioxide  of  iron        .                 

0*52 

0-94 

Phosphoric  acid    .         .              

12'54 

7-33 

Silicic  acid     ..                             

1'85 

9-68 

31-82 

37-37 

Total  

100-00 

100-00 

STARCH   IN   THE   STEMS    OF   PALMS.  335 

The  asparagus  shoots  analysed  came  from  the  Botanical  Gar- 
den at  Munich.  The  flowering  shoots  were  cut  close  to  the 
ground,  on  June  20,  1861 ;  the  autumn  shoots  were  cut  in  the 
same  way,  from  the  same  plant,  on  October  28,  1861. 


APPENDIX  B  (page  41) 

ON    THE    STARCH    IN    THE     STEMS    OP    PALMS. 

The  quantity  of  starch  in  one  and  the  same  stem  differs  to  an 
extraordinary  degree  with  the  age  of  the  plant,  and  the  periods  of 
flowering  and  fructification. 

The  generation  of  starch  will  in  some  instances  rapidly  increase 
not  only  within  the  cells,  but  occasionally  even  at  the  expense  of 
the  cellular  tissue.  Thus,  in  the  root-stock  of  Sabal  Mexicana,  an 
abundance  of  starch  is  sometimes  .found,  not  only  in  the  interior 
of  the  cells,  but  also  outside  the  latter.  But  this  phenomena  is 
most  striking  in  the  East  India  Sago  Palms  (Hetroxylori),  in  which 
it  can  be  clearly  observed  that  the  generation  of  starch  proceeds 
in  distinct  periods,  and  is  in  intimate  organic  connection  with  the 
development  of  the  flowers  and  fruit.  The  Malays  are  in  the 
habit  of  speaking  of  the  tree  as  if  it  were  with  young  at  this  pe- 
riod, during  which  it  generates  in  its  interior  a  large  quantity  of 
starch,  forming  the  store  of  organic  matter,  out  of  which  are  to 
be  produced,  after  liquefaction,  new  ligneous  particles,  and  flow- 
ers, and  fruit.  This  statement  is  peculiarly  applicable  to  the  Me- 
troxylon  Rumphii  Mart.  (Sagus  genuina  JKumph).  This  tree, 
which  is  a  perfect  chemical  laboratory  for  the  preparation  of 
starch,  is  monocarpous,  that  is  to  say,  it  flowers  and  bears  fruit 
only  once,  and  then  dies.  It  has  by  that  time  attained  a  height 
of  from  28  to  30  feet.  The  stem,  which  is  cylindrical,  and  more 
than  a  foot  in  diameter,  consists  of  a  mere  shell,  about  one  and  a 
half  to  two  inches  thick,  of  a  whitish  wood  of  no  great  degree 
of  hardness.  Within  the  shell  is  enclosed  a  mass  of  spongy  tissue 
formed  of  interlaced  fibres,  the  cells  of  which  are  filled  with 
starch  granules.  In  the  first  stage  of  growth,  whilst  the  stem 
still  remains  unripe,  if  the  expression  may  be  allowed,  it  contains 
only  an  inconsiderable  quantity  of  starch.  As  growth  progresses, 
and  the  base  of  the  leaf  stalks,  and  the  upper  part  of  the  stem  be- 
gins to  be  covered  with  long  fibrous  filaments  or  prickles,  the 
quantity  of  starch  increases. 

The  period  of  the  greatest  increase  is  indicated  by  the  shed- 
ding of  these  prickles,  and  by  the  leaves  being  covered  with  a 
sort  of  white  rime,  as  if  powdered  lime  had  been  dusted  over 
them.  The  Malays  call  this  stage  the  Maaputih,  i.  e.  the  tree 


336  APPENDIX  B. 

grows  white.  From  the  apex  of  the  stem  shoots  forth  at  this 
stage  the  flower-stalk,  which  at  a  later  period  crowns  the  tree  like 
an  immense  antler,  bearing  thousands  of  flowers,  which  are  re- 
placed afterwards  by  spherical  fruit  covered  with  scales.  "When 
the  flower-stalk  attains  a  length  of  one  foot,  the  tree  has  entered 
that  stage  which  the  Malays  term  Saga  bonting,  that  is  with 
young.  A  small  quantity  of  the  starch  is  now  taken  up  for  the 
formation  of  the  woody  fibre  of  the  flower-stalks.  Finally  arrives 
the  period  which  the  Malays  term  Majang  bara,  i.  e.  the  young 
comes  forth.  The  flower-stalk  at  the  apex  of  the  stem  now  at- 
tains a  length  of  four  feet,  but  the  spathes  out  of  which  the  floral 
branches  are  to  project,  are  not  yet  opened.  The  tree  may  pass 
through  these  three  stages  without  any  great  reduction  of  the  store 
of  starch ;  but  at  the  next  stage,  termed  Batsja  Bang,  i.  e.  the 
shoot  branches  out,  when  the  flower  stalk  measures  from  six  to 
tea  feet  in  height,  and  ten  feet  in  circumference,  the  greater  por- 
tion of  the  starch  is  formed  into  thick  woody  fibre,  and  still  more 
is  this  the  case  in  the  two  last  stages  of  the  flower  (Siriboa)  and 
fruit  (Bahoa),  when  there  remains  no  longer  any  starch.  A  healthy 
tree  produces  between  400  and  800  Ibs.  of  starch  (the  sago  pre- 
pared from  this  is  not  sent  to  the  European  markets,  but  is  con- 
sumed in  the  country).  The  palm,  which  produces  the  chief  por- 
tion of  the  sago  consumed  in  Europe,  is  the  Metroxylon  laeve 
Mart,  of  Malacca, 'the  wild  stems  of  which  give  four  to  five  and  a 
half  picols  of  sago,  whilst  two  to  three  picols  only  are  obtained 
from  those  cultivated  in  gardens. 


APPENDIX  0  (page  66). 

VEGETABLE    STATICS,    LONDON,    1727. 

The  experiments  made  by  Hales  on  the  motion  of  the  sap  in 
vegetables,  may  be  looked  upon  as  the  best  model  for  all  times  of 
the  most  perfect  method  of  investigation.  That  they  are  still  at 
the  present  day  unsurpassed  in  vegetable  physiology  may,  per- 
haps, be  attributed  to  the  circumstance  of  their  dating  from  the 
age  of  Newton.  They  deserve  a  place  in  every  work  treating  of 
the  physiology  of  plants. 

In  the  beginning  of  his  work  Hales  describes  the  experiments 
made  by  him  on  the  motion  of  the  sap  in  vegetables  arising  from 
the  exhalation  from  their  surface.  These  experiments  were  made 
with  leafy  branches,  plants  cut  off  from  the  roots,  and  others  still 
retaining  their  roots. 

The  force  of  the  pressure  of  a  column  of  water,  both  with  and 
without  the  cooperation  of  exhalation,  was  shown  by  the  follow- 
ing experiment. 


337 

He  fixed  an  apple-branch,  three  feet  long,  half-inch  in  diameter, 
full  of  leaves  and  lateral  shoots,  to  a  tube  seven  feet  long,  and  five- 
eighths  of  an  inch  in  diameter.  He  filled  the  tube  with  water, 
arid  then  immersed  the  whole  branch  up  to  the  lower  end  of  the 
tube,  in  a  vessel  full  of  water.  The  water  was  driven  into  the 
branch  by  the  pressure  of  the  column  of  water  in  the  tube,  which 
Subsided  fourteen  and  a  quarter  inches  in  two  days. 

On  the  third  day  he  removed  the  branch  and  tube  out  of  the 
water,  and  hung  it  up  in  the  open  air ;  the  water  in  the  tube  fell 
now  twenty-seven  inches  in  twelve  hours. 

To  determine  the  comparative  force  with  which  the  water  is 
driven  through  the  vessels  of  the  ligneous  body  by  pressure  alone, 
and  by  pressure  and  exhalation  combined,  Hales  joined  a  leafy  ap- 
ple branch  to  a  tube  nine  feet  long  filled  with  water.  In  conse- 
quence of  the  pressure  of  the  column  of  water  and  of  the  exha- 
lation taking  place  from  the  surface  of  the  leaves  and  twigs,  the 
water  in  the  tube  (fortieth  experiment)  sank  36  inches  in  an  hour. 
He  then  cut  off  the  branch  13  inches  below  the  glass  tube,  and 
placed  the  cut  portion  (with  leaves  and  twigs)  upright  in  a  vessel 
with  water.  It  was  found  to  imbibe  18  ozs.  of  water  in  30  hours ; 
in  which  time  only  6  ozs.  of  water  had  passed  through  the  13 
inches  of  the  stem  connected  with  the  tube,  and  that  too  under 
the  pressure  of  a  column  of  water  7  feet  high. 

In  three  other  experiments,  Hales  shows  that  though  the  sap- 
vessels  of  plants  will  imbibe  water  plentifully  by  capillary  attrac- 
tion in  branches  severed  from  the  trunk,  as  well  as  in  those  left  in 
connection  with  the  uninjured  roots,  they  have  very  little  power 
to  protrude  sap  out  at  their  extremities,  and  make  it  rise  in  a  tube 
fixed  to  them. 

The  motion  of  the  sap,  Hales  concludes,  is  to  be  attributed  to 
the  exhalation  from  the  surface  alone,  and  he  proves  that  it  pro- 
ceeds in  an  equal  degree  from  the  trunk,  branches,  leaves,  flower 
and  fruit,  and  that  the  effect  of  the  exhalation  bears  a  certain  def- 
inite ratio  to  the  temperature  and  moisture  of  the  air.  When  the 
atmosphere  was  charged  with  humidity  little  water  was  imbibed, 
and  on  rainy  days  the  absorption  was  barely  perceptible.  Hales 
opens  this  second  chapter  of  his  statics  with  the  following  intro- 
troductory  remarks  : — 

'  Having  in  the  first  chapter  seen  many  proofs  of  the  great 
quantity  of  liquid  imbibed  and  perspired  by  vegetables,  I  propose 
in  this  to  inquire  with  what  force  they  do  imbibe  moisture. 

'  Though  vegetables  (which  are  inanimate)  have  not  an  engine 
which  by  its  alternate  dilatations  and  contractions  does  in  animals 
forcibly  drive  the  blood  through  the  arteries  and  veins,  yet  has 
nature  wonderfully  contrived  other  means,  most  powerfully  to 
raise  and  keep  in  motion  the  sap.' 

In  his  twenty-first  experiment  he  laid  bare  one  of  the  chief 
roots  of  a  thriving  pear-tree  at  a  depth  of  2*  feet,  cut  off  the  end 

15 


338  APPENDIX   0, 

of  the  root,  and  connected  the  remaining  stump  with  a  glass  tube 
filled  with  water  and  confined  by  mercury.  This  glass  tube  rep- 
resents the  root  lengthened. 

By  the  perspiration  from  the  surface  of  the  tree,  the  root  im- 
bibed the  water  in  the  tube  with  such  vigor  that  in  six  minutes 
the  mercury  had  risen  in  the  tube  as  high  as  8  inches,  which  cor- 
responds to  a  column  of  water  9  feet  in  height. 

This  force  is  very  nearly  equal  to  that  with  which  the  blood 
moves  in  the  great  crural  artery  of  a  horse.  '  I  found,'  says  Hales, 
in  his  thirty-sixth  experiment,  '  the  force  of  the  blood  of  several 
animals,  by  tying  them  down  alive  upon  their  backs,  then  laying 
open  the  great  crural  artery  where  it  first  enters  the  thigh,  and 
fixing  to  it,  by  means  of  two  brass  pipes  running  one  into  the 
other,  a  glass  tube  above  ten  feet  long  and  one-eighth  of  an  inch 
in  diameter.  In  this  tube  the  blood  of  one  horse  rose  eight  feet 
three  inches,  and  the  blood  of  another  horse  eight  feet  nine  inches ; 
the  blood  of  a  little  dog,  six  feet  and  a  half.' 

Hales  proved  by  special  experiments^  that  the  force  of  suction 
shown  by  him  to  be  possessed  by  the  roots  of  plants,  is  exercised 
equally  by  every  individual  branch,  shoot,  leaf,  and  fruit,  in  short, 
by  every  portion  of  the  surface  ;  that  the  motion  of  the  sap  from 
the  root  to  the  branches  and  leaves  continues  even  when  the 
trunk  is,  in  any  part,  completely  stripped  of  the  outer  and  inner 
bark,  and  that  this  force  of  suction  acts  not  only  from  the  roots 
towards  the  top,  but  also  from  the  latter  towards  the  roots. 

He  concludes,  from  the  results  of  his  experiments,  that  every 
part  of  the  plant  is  endowed  with  a  powerful  force  of  attraction. 

"We  know  now  that  it  was  not  this  force  of  attraction  in  itself 
that  made  the  mercury  and  the  water  rise  in  Hales'  tubes ;  and 
his  experiments  clearly  show,  that  the  imbibing  force  of  plants, 
and  of  every  leaf  and  root  fibre,  arising  from  surface  exhalation,  is 
aided  by  a  powerful  force  from  without,  which  is  simply  atmo- 
spheric pressure. 

By  the  evaporation  of  the  water  from  the  surface  of  plants  a  vacu- 
um is  created  therein,  and  in  consequence  thereof  water  and  gases 
soluble  in  that  fluid  are  readily  forced  in  from  without  and  raised 
by  the  pressure  of  the  atmosphere,  and  it  is  this  pressure  from 
without  which,  together  with  capillary  attraction,  constitutes  the 
principal  cause  of  the  motion  and  diffusion  of  the  sap. 

That  the  surface  of  plants  possesses  the  faculty  of  imbibing 
gases,  is  most  conclusively  demonstrated  by  Hales.  In  his  twenty- 
second  experiment  he  says : — '  The  height  to  which  the  mercury 
rose  in  the  tube  did  in  some  measure  show  the  force  with  which 
the  sap  was  imbibed,  though  not  nearly  the  whole  force ;  for  while 
the  water  was  imbibing,  the  transverse  cut  of  the  branch  was  cover- 
ed with  innumerable  little  hemispheres  of  air,  and  many  air-bubbles 
issued  out  of  the  sap-vessels,  which  air  did  in  part  fill  the  tube  as 
the  water  was  drawn  out  of  it ;  so  that  the  height  of  the  mercury 


HALES'  EXPERIMENTS.  339 

could  only  be  proportionable  to  the  excess  of  the  quantity  of  water 
drawn  off,  above  the  quantity  of  air  which  issued  out  of  the  wood. 

'  And  if  the  quantity  of  air,  which  issued  from  the  wood  into 
the  tube,  had  been  equal  to  the  quantity  of  water  imbibed,  then 
the  mercury  would  not  have  risen  at  all,  because  there  would 
have  been  no  room  for  it  in  the  tube. 

'  But  if  nine  parts  in  twelve  of  the  water  be  imbibed  by  the 
branch,  and  in  the  meantime  but  three  such  parts  of  air  issue  into 
the  tube,  then  the  mercury  must  needs  rise  near  six  inches,  and  so 
proportionately  in  different  cases.' 

When,  in  Hales'  experiments,  the  root,  the  stem,  or  a  branch 
had  been  wounded  in  any  part  by  cutting  off  root  fibres,  or  buds, 
or  smaller  twigs,  the  imbibing  power  was  found  to  be  diminished 
in  the  other  parts  (because  at  those  wounded  spots  the  difference 
in  the  pressure  was  more  readily  equalized  by  air  finding  its  way 
in).  The  imbibing  power  was  greatest  about  fresh  cuts,  but  it 
gradually  diminished  until,  after  a  few  days,  it  remained  no  stronger 
about  the  cut  than  about  the  uninjured  parts.  Hales  further  con- 
cludes the  exhalation  from  the  surface  to  be  the  powerful  cause 
that  conveys  nutriment  to  the  plant  from  the  parts  surrounding  it. 
If  the  proper  proportion  between  the  exhalation  and  the  supply 
of  food  is  in  any  way  disturbed,  the  plant  sickens  and  dies.  If,  in 
hot  summers,  the  soil  is  unable  to  supply  to  the  roots  the  moisture 
carried  off  in  the  course  of  the  day  by  exhalation  from  the  leaves, 
&c.,  and  the  tree  or  a  branch  of  it  is  dried  up,  the  motion  of  the 
sap  ceases  in  such  parts.  Once  dried  up,  the  original  action  can- 
not be  restored  by  capillary  attraction  alone.  Exhalation  is  the 
chief  condition  of  the  life  of  the  plant,  serving  as  it  does,  to  effect 
and  maintain  a  continual  motion  of  the  sap,  and  a  constantly  re- 
curring change  in  its  condition. 

'  By  comparing,'  says  Hales,  '  the  surface  of  the  roots  of  a 
plant  with  the  surface  of  the  same  plant  above  ground,  we  see  the 
necessity  of  cutting  off  many  branches  from  a  transplanted  tree. 
Suppose,  upon  digging  the  plant  up,  in  order  to  transplant  it,  half 
the  roots  be  cut  off  (which  is  the  case  of  most  young  transplanted 
trees),  then  it  is  plain  that  but  half  the  usual  nourishment  can  be 
carried  up  through  the  roots,  and  that  accordingly  the  perspiring 
surface  above  ground  must  be  correspondingly  reduced  in  order  to 
restore  the  proper  proportion  between  it  and  the  imbibing  surface 
under  ground.'  In  the  following  observations  on  hop  vines,  Hales 
shows  the  effect  of  suppressed  perspiration  :  — 

'  The  soil  of  an  acre  of  ground  on  which  9,000  hop-vines  are 
growing,  must  supply  to  the  plants,  through  the  roots,  in  July, 
36,000  ozs.  of  water  in  twelve  hours.  This  is  the  quantity  of 
water  which  during  this  time  is  exhaled  by  them,  and  which  they 
must  have  to  be  in  a  thriving  condition. 

'  In  a  kindly  state  of  the  air,  this  moisture  is  daily  carried  off 
in  sufficient  quantity  to  keep  the  hops  in  a  healthy  state  ;  but  in  a 


340  APPENDIX   C. 

rainy  moist  state  of  air,  without  a  due  mixture  of  dry  weather,  too 
much  moisture  hovers  about  the  hops,  so  as  to  hinder,  in  a  great 
measure,  the  kindly  perspiration  of  the  leaves,  whereby  the  stag- 
nating sap  corrupts  and  breeds  mould. 

'  This  was  the  case  in  the  year  1723,  when  ten  or  fourteen  days 
almost  continual  rains  fell",  about  the  latter  half  of  July,  after  four 
months'  dry  weather ;  upon  which  the  most  flourishing  and  prom- 
ising hops  were  all  infested  with  mould  in  their  leaves  and  fruit, 
while  the  then  poor  and  unpromising  hops  escaped  and  produced 
plenty ;  because  they  being  small,  did  not  perspire  so  great  a 
quantity  as  the  others ;  nor  did  they  confine  the  perspired  vapor 
so  much  as  the  large  thriving  vines  did  in  their  shady  thickets. 

'  This  rain  on  the  then  warm  earth  made  the  grass  shoot  out  as 
fast  as  if  it  were  in  a  hotbed ;  and  the  apples  grew  so  precipitately, 
that  they  were  of  a  very  fleshy  constitution,  so  as  to  rot  more  re- 
markably than  had  ever  been  remembered. 

'  The  planters  observe,  that  when  mould  has  once  seized  any 
part  of  the  ground,  it  soon  runs  over  the  whole,  and  that  the  grass 
and  other  herbs  under  the  hops  are  infected  with  it ;  probably 
because  the  small  seeds  of  this  quick  growing  mould,  which  soon 
come  to  maturity,  are  blown  over  the  whole  ground ;  which 
spreading  of  the  seed  may  be  the  reason  why  some  grounds  are 
infected  with  fen  for  several  years  successively. 

'  I  have,'  says  Hales,  '  in  July  (the  season  for  fire-blasts,  as  the 
planters  call  them),  seen  the  vines  in  the  middle  of  a  hop  ground 
all  scorched  up,  almost  from  one  end  of  a  large  ground  to  the 
other,  when  a  hot  gleam  of  sunshine  has  come  immediately  after 
a  shower  of  rain ;  at  which  time  the  vapors  are  often  seen  with 
the  naked  eye,  but  especially  with  reflecting  telescopes,  to  ascend 
so  plentifully  as  to  make  a  clear  and  distinct  object  become  imme- 
diately very  dim  and  tremulous.  ISTor  was  there  any  dry  gravelly 
bed  in  the  ground,  along  the  course  of  this  scorch.  It  was,  there- 
fore, probably  owing  to  the  much  greater  quantity  of  scorching 
vapors  in  the  middle  than  outside  of  the  ground,  and  that  being  a 
denser  medium,  it  was  much  hotter  than  a  more  rare  medium. 

'  The  gardeners  about  London  have,  to  their  cost,  too  often  had 
occasion  to  observe  a  similar  eifect,  when  they  have  incautiously 
put  bell-glasses  over  their  cauliflowers  early  on  a  frosty  morning, 
before  the  dew  was  evaporated  off  them ;  which  dew  being  raised 
by  the  sun's  warmth,  and  confined  within  the  glass,  did  then  form 
a  dense  transparent  scalding  vapor,  which  burnt  and  killed  the 
plants.' 

These  observations  translated  into  the  language  of  the  present 
day  clearly  show  how  acutely  and  exactly  Hales  comprehended 
the  influence  of  perspiration  upon  the  life  of  plants. 

According  to  him,  the  proper  thriving  of  plants  depends  upon 
the  supply  of  food  and  moisture  from  the  soil,  which  again  is  gov- 
erned in  a  measure  by  a  certain  temperature  and  dry  ness  of  the 


DRAINAGE  WATER. 


atmosphere.  The  imbibing  power  of  plants, — the  motion  of  the 
sap  in  them,  is  dependent  upon  exhalation ;  the  quantity  of  food 
imbibed  and  needed  for  the  functions  of  the  plant,  is  proportionate 
to  the  quantity  of  moisture  exhaled  in  a  given  time.  If  the  plant 
has  imbibed  a  maximum  of  fluid,  and  the  exhalation  is  hindered  by 
a  low  temperature,  or  by  long  continued  wet  weather,  the  supply 
of  food  or  the  nutrition  of  the  plant  stops,  the  sap  stagnates,  and 
an  alteration  ensues  tending  to  the  generation  of  parasitical  mi- 
croscopic growths.  If  rain  falls  after  hot  weather,  followed  by  a 
strong  heat  without  wind,  and  every  part  of  the  plant  is  surround- 
ed with  an  atmosphere  saturated  with  moisture,  cooling  by  further 
exhalation  ceases,  and  the  plants  succumb  to  the  sun-blasts. 


APPENDIX  D  (page  98). 

ANALYSES    OF   DRAINAGE,   LTSIMETER,    RIVER  AND   MARSH 


WATER. 


I. — Drainage  Water. 

Thomas  Way  found  in  drainage  water  taken  from  seven  differ- 
ent fields,  the  following  constituents  ('  Journal  of  the  Roy.  Agric. 
Soc.,'  vol.  xvii.  133)  :— 


Grains  in  1  gallon  =  10,000  grains  of  water. 


1 

2 

3 

4 

5 

6 

7 

Potash     

trace 

trace 

0'02 

0*05 

trace 

0*22 

trace 

Soda     

TOO 

2'17 

2'26 

0*87 

1*42 

1*40 

3*20 

Lime                   .           ... 

4*85 

7*19 

6  '05 

2*26 

2*52 

5*82 

13*00 

Magnesia           ....            . 

0*68 

2*32 

2*48 

0*41 

0*21 

0*93 

2*50 

Sesquioxide  of  iron  and  ) 
alumina  j 

0'40 

0-05 

o-io 

1-30 

0*35 

0*50 

Silicic  acid  

0-95 

0-45 

0*55 

1'20 

1*80 

0'65 

0*85 

Chlorine                      . 

0'70 

1*10 

1*27 

0'81 

1*26 

1*21 

2*62 

Sulphuric  acid 

1*65 

5*15 

4  "40 

1'71 

1*29 

3*12 

9'51 

Phosphoric  acid 

trace 

0*12 

trace 

0*08 

0*06 

0*12 

Ammonia 

0'018 

O'OIS 

0*018 

0*012 

0*018 

0*018 

0*006 

Very  similar  results  were  obtained  by  Dr.  Krocker  in  his  analy- 
ses of  drainage  water  from  Proskau.  (See  Liebig  and  Kopp's 
'  Jahresbericht '  for  1853,  page  742.) 


342 


APPENDIX   D. 


Drainage  Water  (in  10,000  parts). 

a 

6 

c 

d 

e 

/* 

Organic  matter  

0-25 

0-84 
2'08 
0.02 
0-70 
0-04 
0-02 
O'll 
0-08 
0-07 

0-24 
0-84 
2-10 
0-02 
0-69 
0-04 
0'02 
0-15 
0-08 
0-07 

0-16 
1-27 
1-14 

o-oi 

0-47 
0-04 
0-02 
0'13 
0-07 
0-015 

0-06 
0-79 
0-17 
0-02 
0-27 
0-02 
0-02 

o-io 

0-03 
0-05 

0-63 
0-71 
0-77 
0'02 
0-27 
0-02 
0-04 
0'05 

o-oi 

0-06 

0-56 

0-84 
0-72 
0-02 
0-16 

o-oi 

0'06 
0-04 

o-oi 

O'Oo 

Sulphate  of  lime  

Carbonate  of  magnesia- 

Carbonate  of  protoxide  of  iron.  .  . 
Potash 

Soda  

Silica  

Total  solid  matter  

4-21 

4-25 

3'37 

1-53 

2-58 

2-47 

II. — Lysimeter   Water. 

Lysimeter  water  is  atmospheric  water  passed  by  means  of  suit- 
able apparatus  (Lysimeter)  through  different  soils,  and  collected 
after  passing  through.  (See  pp.  99,  100.) 

The  chemical  analyses  embraced  four  series,  and  were  made  by 
Dr.  Zoeller. 


1. — Series  of  analyses  made  in  1857. 

The  experiments  were  made  with  five  different  soils,  1  square 
foot  of  each  earth,  6  inches  deep,  being  placed  in  the  several 
lysimeters.  The  quantities  given  represent  the  amount  of 
atmospheric  water  that  passed  through  the  several  lysimeters 
from  April  T  to  October  V,  185T.  I.  Manured  calcareous  soil, 
with  vegetation  (barley).  II.  Unmanured  clay  soil,  with  vege- 
tation. III.  Unmanured  clay  soil,  without  vegetation.  IV. 
Manured  clay  soil,  without  vegetation.  Y.  Manured  clay  soil, 
with  vegetation.  (2  Ibs.  cattle-dung,  without  straw,  were  sev- 
erally used  to  manure  the  earth  in  lysimeters  I.,  IV.,  and  V. 


*  a.  Drainage  water  from  land  A  (a  clay  soil  resting  on  a  subsoil  of  cal- 
careous loam  or  clay),  collected  1st  April,  1853. — b.  The  same,  collected  1st 
May,  1853,  after  a  heavy  fall  of  rain  (218  cubic  inches  on  the  square  foot). — 
c.  Drainage  water  from  the  same  soil,  mixed  with  drainage  water  from  a 
humous  clay  soil,  with  calcareous  clay  or  loam  as  subsoil,  collected  in  Octo- 
ber, 1853. — d.  Drainage  water  from  land  B  (tile-drained;  subsoil  of  calcare- 
ous clay  or  loam),  collected  in  October,  1853. — e.  Water  passing  through  the 
water-furrows  from  a  heavy  clay  soil,  collected  in  the  beginning  of  June. — 
f.  The  same,  collected  in  the  middle  of  August,  after  heavy  rains. 


LYSIMETEE   WATER. 


343 


I. 

II. 

III. 

IV. 

V. 

Quantity    of  water   passed  ) 
through  soil  in  lysimeter.  ) 

Solid  residue  left  at  212°  F  
Ash  of  solid  residue                • 

cub.  cent. 

9845 

grammes. 
4-651 
3-127 

cub.  cent. 
18575 

grammes. 
4-73 

3-283 

cub.  cent. 
18148 

grammes. 
5-291 
3-545 

cnb.  cent. 
19790 

grammes. 

"  6-04 
4-245 

cub.  cent. 
12302 

grammes. 
3-686 
2-610 

Potash  

0-064 
0-070 
1-436 
0-203 
0-013 
0-566 
0-022 
0-172 
0-103 
0-089 

C-044 
0104 
1-070 
0-165 
0-119 
0-177 
trace 
0-504 
0-210 
0-074 

0-037 
0-135 
1-285 
0-024 
0-150 
0-379 
trace 
0-515 
0-317 
0-112 

0-108 
0-470 
1-354 
0-058 
0-114 
0-781 
trace 
0-580 
0-188 
0-045 

0-047 
0-074 
1-136 
0-063 
0-053 
0-434 
trace 
0-412 
0-115 
0-047 

Soda  

Magnesia                        . 

Sesquioxide  of  iron      .  .  .... 

Chlorine                .   ...       .... 

Phosphoric  acid         

Sulphuric  acid  

Silicic  acid  

Total  

2-738 
0127 

2-467 
0-040 

2-954 
0-OS5 

3-698 
0-176 

2-381 
0-095 

Deduct  equivalent  of  oxygen  ) 
corresponding  to  chlorine  ) 

Balance 

2-611 
2-040 

4-651 

2-427 
2-303 

4-730 

2-869 
2-422 

5-291 

3-522 
2-518 

2-286 
1-400 

Carbonic  acid  and  loss  
Total  

6-040 

3-686 

1,000,000  litres  of  water,  passed  through  six  inches  of  the  soils 
already  described,  contain — 


I. 

II. 

III. 

IV. 

V. 

Solid  residue  left  at  212°  F.  .  .  . 
Ash  contained  in  it  ....       ... 

grammes. 
472-32 
317-62 

grammes. 

254-64 
176-74 

grammes. 
292-64 
194-78 

grammes. 

"305-20 
214-50 

grammes. 
291-50 
212-16 

Potash  

6-50 
7-11 
145-86 
20-52 
1-32 
57-49 
2-23 
17-47 
10-46 

2-37 
5-60 
57-60 
8-88 
6-35 
9-52 

2-03 
JT-43 
70-80 
1-32 
8-26 
20-87 

27-82 
17-46 

5-46 
23-74 
68-41 
2-93 
5-76 
39-46 

3-82 
6-02 
92-34 
5-12 
4-30 
35-27 

33-49 
9-34 

Soda  

Lime       

Chlorine 

Phosphoric  acid 

Sulphuric  acid 

27-13 
11-35 

29-30 
9-50 

Silicic  acid  (soluble) 

2. — Series  of  analyses  made  in  1858. 

The  waters  analysed  were  obtained  from  six  soils,  and  repre- 
sent the  quantity  of  atmospheric  water  tnat  passed,  from  May  10 
to  Nov.  1,  1858,  through  a  layer  of  earth  of  a  square  foot  of 
surface  and  12  inches  deep.  The  earth  was  ordinary  unmanured 
alluvial  lime  soil  from  the  Isar.  The  plant  selected  for  cultiva- 
tion was  the  potato.  I.  Unmanured,  and  without  vegetation. 


344 


APPENDIX   D. 


II.  Unmanured,  with  vegetation.  III.  Manured,  10  grammes 
common  salt,  with  vegetation.  IV.  Manured,  10  grammes 
nitrate  of  soda,  with  vegetation.  V.  10  grammes  guano,  with 
vegetation.  VI.  Manured,  20  grammes  phosphorite  made  soluble 
with  hydrochloric  (?)  acid,  with  vegetation. 


I. 

II. 

III. 

IV. 

V. 

VI. 

Quantity  of  water  passed  ) 
through,  the  soil  f 

cu.  cent. 

29185 

cu.  cent. 
25007 

cu.  cent. 

2S138 

cu.  cent. 
17466 

cu.  cent. 
16520 

cu.  cent. 
S0850 

Solid  residue  left  at  212°  F. 
Ash  of  the  solid  residue.  .  . 

grms. 
8-985 
6-591 

grms. 

8-214 
6-094 

grms. 
14-198 
12-292 

grms. 

7-681 
5-553 

grms. 
4-864 
3-704 

frms. 
•001 
6-192 

Soda              .     .. 

0'250 

0-245 

3-290 

1-255 

0*301 

0*233 

Potash               

0-075 

0'066 

0'034 

0-035 

0-032 

0'029 

0-432 

0-443 

0-454 

0-264 

0-382 

0-374 

2-416 

2-467 

2*356 

1-792 

1-378 

2'645 

Oxide  of  iron        . 

0'115 

0'033 

0-104 

0'083 

0-096 

0-117 

Chlorine       

0'227 

0-237 

3-925 

0-177 

0-317 

0*238 

Phosphoric  acid       

trace 

trace 

0'009 

trace 

0-007 

0-015 

3-267 

0-132 

0-147 

0-118 

0-182 

0-197 

0-666 

0-266 

0-301 

0-384 

0-303 

0-226 

0-224 

Sand  

0-155 

0-237 

0-155 

0-105 

0-062 

0-083 

4-068 

4-226 

10-829 

7-463 

2-998 

4-644 

Less  the  amount  of  oxy-  ) 
gen  equivalent  to  the  > 
chlorine                        .  ) 

0-051 

0-053 

0-884 

0-039 

0-071 

0*053 

Sum 

4-017 

4*163 

9-945 

7-424 

2*927 

4-591 

Loss  and  carbonic  acid.  .  .  . 

4-968 

4-051' 

4-253 

0-257 

1*937 

3-410 

Sum               .         .... 

8'985 

S'214 

14-198 

7-671 

4*864 

8*001 

1,000,000  litres  of  water,  passed  through  10  inches  of  the  soils 
already  described,  contain — 


I. 

II. 

III. 

IV. 

V. 

VI.  . 

Solid  residue  left  at  212°  F. 
Ash  contained  in  it  .... 

grms. 

307.86 
225*83 

grins. 
328*46 
243*69 

grms. 

504-58 
436-84 

grms. 
439-76 
374-04 

grms. 
294-42 
224*21 

grms. 
259-35 
200-71 

Soda      

8'56 

9-79 

116*92 

71-85 

18-22 

7-55 

Potash      

2'56 

2'63 

1-20 

2'00 

1-93 

0*94 

Magnesia  

14*80 

17*71 

16-13 

15-11 

23*18 

12-12 

Lime  

82*78 

98*65 

83'73 

102-59 

83-41 

8573 

Oxide  of  iron  

3*94 

3*31 

3'69 

4-75 

5'81 

379 

Chlorine  

7*77 

9*47 

139*49 

10*13 

19-18 

7-71 

0-31 

0-42 

0*48 

Nitric  acid 

187*04 

Sulphuric  acid  

4-52 

5*87 

4*19 

10*42 

11-09 

21-59 

Silicic  acid... 

9-11 

12-03 

13-64 

17-34 

13-68 

7*26 

LYSIMETER   WATEK. 


345 


3. — Series  of  analyses  made  in  1859. 

The  waters  analysed  were  obtained  from  six  soils,  and  repre- 
sent the  quantity  of  atmospheric  water  that  passed  from  March 
20  to  Nov.  16,  1859,  through  a  layer  of  earth  of  a  square  foot  of 
surface  and  12  inches  deep.  The  earth  was  ordinary  unmanured 
alluvial  lime  soil  from  the  Isar  (garden  soil).  All  the  soils  were 
in  grass.  I.  Unmanured.  II.  Manured,  17'8  grammes  nitrate  of 
potash.  III.  Manured,  15 -4  grammes  sulphate  of  potash.  IV. 
Manured,  17*8  grammes  nitrate  of  potash,  and  3*66  grammes 
phosphoride  made  soluble  with  2  grammes  sulphuric  acid.  V. 
Manured,  15'4  grammes  sulphate  of  potash,  and  3'66  grammes 
of  phosphorite  made  soluble  as  above.  VI.  Manured,  12'3 
grammes  carbonate  of  potash. 


I. 

II. 

III. 

IV. 

V. 

VI. 

Quantity  of  water  passed  ) 
through  the  soil  j 

cu.  cent, 
20201 

grins. 
4-5631 
3-192 

cu.  cent. 

14487 

grms. 
11-4272 
8-861 

cu.  cent. 

20348 

grms. 
15-1967 
13-644 

cu.  cent. 
17491 

grms. 
13-6805 
10-681 

cu.  cent. 

23205 

grms. 
20-784 
17-668 

cu.  cent. 
22488 

grms. 
5-5873 
4-614 

Solid  residue  left  at  212°  F. 
Ash  of  the  solid  residue.  .  . 

Soda  . 

0-044 
0-024 
0-253 
1-530 
0-072 
0-035 
trace 
0-289 
1-125 
0-178 
0-044 

0-069 
0-166 
0-302 
3-483 
0-057 
0-080 
trace 
0-205 
5-913 
0-271 
0-021 

0-083 
0-205 
0-296 
5-360 
0-072 
0-202 
trace 
6-527 
1-301 
0-208 
0-036 

0-030 
0-231 
0-285 
4-838 
0-084 
0-132 
trace 
2-104 
5-248 
0-230 
0-025 

0-085 
0-244 
0-320 
7-112 
0-088 
0-283 
trace 
9-124 
1-401 
0-280 
0-056 

0-038 
0-112 
0-117 
1-963 
0-053 
0-127 
trace 
1-524 
1-390 
0-269 
0-097 

Potash 

Lime                   . 

Phosphoric  acid  
Sulpnuric  acid  

Nitric  acid 

Silicic  acid    .   . 

Sand  

Sum 

3-594 
0'007 

10-567 
0-018 

14-290 
0-045 

13-207 
0-029 

18-993 
0-063 

4-690 
0-028 

Less  the  amount  of  oxy-  ) 
gen  equivalent  to  the  > 
chlorine  ) 

Sum  

3-587 
0-9761 

10-549 
0-8782 

14-245 
0-9517 

13-178 
0-5025 

18-930 
1-854 

4-662 
0-9258 

Loss  and  carbonic  acid.  .  .  . 
Sum..   .. 

4-5631 

11-4372 

15-1967 

13-6805 

20-784 

5-5878 

1,000,000  litres  of  water,  passed  through  one  foot  of  the  soils 
already  described,  contain — 


15* 


346 


APPENDIX  D. 


I. 

II. 

III. 

IV. 

V. 

YI. 

Solid  residue  left  at  21  2C  F. 
Ash  cunt  allied  in  it 

grms. 

225-38 
158*0 

grms. 

788-78 
611-64 

?rms. 
746-84 
670*52 

grms. 
782-14 
610*65 

grms. 
895-66 
761*36 

grms. 

248-48 
205*17 

Soda                    '. 

2-17 

4-76 

4-07 

1*71 

3'66 

1*68 

Potash.   

1-18 

11-45 

10'07 

13-20 

10*51 

4*98 

Magnesia  

12-52 

20'84 

14-54 

16-29 

13*79 

5-20 

Lime  

75-73 

240-42 

263-41 

276-59 

306-48 

87*29 

Oxide  of  iron  

3-56 

3-93 

3-53 

4'80 

3-79 

2*35 

Chlorine  

1-73 

5-52 

9'92 

7-54 

12-19 

5*64 

14-30 

14-15 

320-76 

120-29 

393-19 

23-30 

Nitric  acid 

55-69 

408'15 

63-93 

300-04 

60'37 

61*76 

Silicic  acid 

8'81 

18'70 

10'32 

13-14 

12'06 

11*96 

4. — Series  of  analyses  made  in  1859,  1860. 

This  series  is  a  direct  continuation  of  the  third.  The  waters 
analysed  passed  through  the  same  soils  through  which  the  waters 
of  the  third  series  had  already  passed.  The  fourth  series  of  ex- 
periments continued  from  Nov.  16,  1859,  to  April  12,  1860. 


I. 

II. 

III. 

IV. 

V. 

VI. 

Quantity  of  water  passed  ) 
through  the  soil             f 

cu.  cent. 
13500 

grms. 

2-424 
2-071 

cu.  cent 
12332 

grms. 

2-205 
1-682 

cu.  cent. 
13760 

grms. 
2-860 
2-395 

cu.  cent. 
13150 

grms. 
2-640 
2-086 

cu.  cent. 

15232 

grms. 
3-172 
2-599 

cu.  cent. 

14850 

grms. 
2-691 
2*220 

Solid  residue  left  at  212°  F. 
Ash  of  the  solid  residue  .  .  . 

Soda  

0'021 
trace 
0-065 
0-770 
0-061 
0-140 
trace 
0-025 
0-119 
0-170 

0-024 
0-008 
0-058 
0-859 
0-066 
0-042 
trace 

0-101 

0-099 
0-144 

0*028 
0-012 
0-069 
1-016 
0*097 
0-093 
trace 
0*043 
0-487 
0-118 

0-022 
0-009 
0-074 
0-938 
0-075 
0-068 
trace 
0-077 
0-474 
0-153 

0-028 
0-015 
0-070 
0*952 
0*135 
0*091 
trace 
0*029 
0-527 
0-123 

0-019 
0-015 
0-063 
1-057 
0-049 
0*084 
trace 
0*046 
0-185 
0-136 

Potash  

Oxide  of  iron 

Chlorine       . 

Phosphoric  acid       .         .  . 

Nitric  acid              .  . 

Sulphuric  acid 

Silica  and  sand*  

Sum  

1-371 
0-024 

1-401 
0-009 

1-963 
0-020 

1-890 
0-015 

1-970 
0-020 

1*654 
0*018 

1-636 
0-955 

Deduct  the   amount    of) 
oxygen   equivalent  to  >- 
the  chlorine                 .  ) 

Sum 

1-347 
1-077 

1*392 
0*813 

1-943 
0-917 

1-875 
0-765 

1-950 

1-222 

Loss  and  carbonic  acid  
Sum.  . 

2-424 

2-205 

2-860 

2-640 

3-172 

2*691 

*  The  quantity  of  sand  very  small. 


LYSIMETEK   WATER. 


347 


1,000,000  litres  of  water,  passed  through  10  inches  of  the  soils 
already  described. 


I. 

II. 

III. 

IV. 

V. 

VI. 

Solid  residue  left  at  212°  F. 

grms. 
179-56 
153'47 

grms. 

178-80 
136-39 

grms. 
207-71 
174*07 

grms. 
200-81 
158-69 

grms. 

208-24 
170-62 

?rms. 
1-21 
149-49 

Soda       

1-56 

1-94 

2-04 

1-73 

1-83 

1-27 

Potash        

0-64 

0-92 

0-69 

0-98 

roi 

Magnesia       

4-86 

470 

5-02 

5-56 

4-59 

4-24 

Lime     ..   ,,.  

57-04 

69-49 

73-87 

71-39 

62-50 

71-17 

4-52 

5-35 

7-06 

5-73 

8-86 

3-29 

10-43 

3-40 

6-76 

5-21 

5-97 

5-65 

1-91 

8-19 

3-17 

5-91 

1-90 

3-09 

8'86 

8'02 

35-45 

36'08 

34-59 

12-45 

Silicic  acid  with  a  little  ) 
sand                     ,            f 

12-60 

11-67 

8-60 

11-65 

8-01 

9-15 

Compare  'Annal  der  Ohem.  und  Phar.,'  bd.  107,  s.  27; 
'Ergebnisse  landwirthsch.  und  Yersuche  der  Yersuchstation, 
Mimchen,'  II.  Heft,  s.  65,  und  III.  Heft,  s.  82. 

Analysis  of  ashes  of  plants  from  the  rivers  Ohe  and  her. — DR.  WITTSTEIN. 


Fontinalis 
from  the  Ohe. 

Antipyretica* 
from  the  Iser. 

0*346 

0'834 

Potash  

0'460 

Soda  

1'745 

|     2-325 

2'755 

18'150 

Magnesia         

1-133 

5*498 

9-272 

1-616 

17"'039 

9-910 

Oxide  of  manganese  

4*555 

0-850 

Sulphuric  acid.       

1-648 

2*827 

Phosphoric  acid  

trace 

5*962 

61-000 

51*494 

Carbonic  acid  

Sum... 

99-953 

99*466 

*  The  great  difference  in  the  composition  of  the  ashes  of  one  and  the  same 
plant  arises,  according  to  Dr.  Niigeli,  less  perhaps  from  the  different  amount 
of  these  matters  in  the  water  than  from  difference  of  age  in  the  plan  is,  and 
probably  more  still  from  other  plants  which  nestle  in  the  moss. 


348 


APPENDIX  D. 


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5*1 


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cot—  icocot-cooocMcoioeo 

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CpCvICNIOSOr-103?— I 

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0-15625 
0-04125 


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11 

1  1  1 


MOSS   WATER. 


349 


IV. — Moss  Water  from  the  neighbourhood  of  Schleissheim. — DR. 
WITTSTEIN. 

The  composition  of  the  water  was  found  to  be  as  follows : — 


In  1000  grammes 
of  water. 

In  100  parts  of 
solid  matter. 

Chloride  of  sodium  ...» 

0*00280 

i-ioi 

0-00022 

0-086 

Soda               

0*00551 

2'167 

Lime        ..   .... 

0'05266 

20*723 

Msgnesia  

0-00921 

3*627 

Alumina  

0'00029 

0-114 

0-00197 

0775 

0'00372 

1-466 

0-00002 

0*008 

0-00069 

0*271 

0-03943 

15-595 

0-13771 

54*067 

Total  amount  of  solid  matter  . 

0-25423 

100*000 

Total  amount  of  inorganic  matter  .  . 

0-11652 

APPENDIX  E  (page  113). 

VEGETATION   OF  LAND  PLANTS   IN  THE   WATERY      SOLUTIONS 
OF   THEIR   FOOD. 

In  experiments  on  the  vegetation  of  land  plants  in  the  watery 
solutions  of  their  food,  great  attention  must  be  paid  to  the  tenden- 
cy of  the  fluid  to  become  alkaline  by  the  process  of  vegetation,  as 
land  plants  always  die  in  alkaline  solutions.  Great  care  must 
therefore  be  taken  to  keep  the  fluid  neutral  (very  faintly  alkaline) 
or  feebly  acid.  Knop  attained  this  object  by  frequently  transfer- 
ring his  plants  to  fresh  solutions ;  Stohmann,  by  placing  the  plants 
from  the  commencement  in  feebly  acid  solutions,  and  at  a  later 
period  transferring  them  sometimes  to  fresh  solutions,  and  at 
other  times  removing  the  alkaline  reaction  by  frequent  addition 
of  a  small  quantity  of  acid. 

The  tendency  of  solutions  to  become  alkaline  by  means  of  the 
plants  vegetating  in  them,  and  the  injurious  effect  of  an  alkaline 
solution  on  the  growth  of  plants,  were  observed  by  Knop  and 
Stohmann. 

In  the  following  are  communicated  the  experiments  of  Knop 
and  Stohmann  on  the  vegetation  of  maize,  in  watery  solutions. 


350 


APPENDIX   E. 


I. — Experiments  of  Knop. 

Knop  based  his  experiments  with  maize  on  the  earlier  observa- 
tions which  he  had  made  on  the  vegetation  of  barley  and  cresses 
(see'Chem.  Central  Blatt,'  1861,  s.  564).  According  to  these 
observations  the  gramnreae  require  for  their  growth  nothing  more 
than  a  normal  solution,  which  contains  sulphate  of  magnesia, 
nitrate  of  lime,  and  nitrate  of  potash,  according  to  the  proportion 
MgOS03  +"2CaON05  +  2KON03,  in  which  phosphate  of  iron  was 
suspended,  and  phosphate  of  potash  as  required  was  dissolved. 
The  normal  solution  A  made  according  to  the  above  formula  con- 
tained in  grammes — 

100  cent.  cub. 
Nitric  acid  . . 


0-2160 

Sulphuric  acid 0*0495 

Lime 0*0684 

Magnesia 0*0233 

Potash 0-0940 

0-4512 


500  cent.  cub. 
1-0800 
0-2475 
0-3420 
0-1165 
0-4700 

2-2560 


600  cent.  cub. 
1-2960 
0-2970 
0-4104 
0-1398 
0-5640 


2-7072 


In  consequence  of  using  the  solution  in  a  more  dilute  form  in 
the  first  period,  in  order  to  promote  a  better  radication,  600  cubic 
centimetres  of  the  above  solution  were  employed  at  this  time  ;  at 
every  other  period,  500  cubic  centimetres  were  measured  off,  and 
to  this  last  quantity  the  phosphate  of  potash  was  now  added  in 
the  proportion  indicated.  The  mixture,  therefore,  had  the  fol- 
lowing composition  in  the  five  periods.  The  potash  which  was 
added  as  KOPOa,  and  as  KONOs,  are  given  separately  and  united 
with  a  bracket. 

Period. 

I.  12  cent.  cub.  solution  of  KOP05(*  600  cent.  cub.  normal  solution  A. 

II.  10          "  "  500          "  " 
III.  &  IV.  20          "                        "                    500          " 

V.        30          "  "  500          "  " 

In  these  solutions  are  contained  in  grammes, — 


Per.  I. 

Per.  II. 

Per.  Ill  &IV. 

Per.  V. 

Nitric  acid  

1*2960 

1*0800 

1-0800 

1-0800 

Sulphuric  acid  

0*2970 

0*2475 

0-2475 

0*2475 

Phosphoric  acid  
Lime  

0-0750 
0*4104 

0-0625 
0'3420 

0-1250 
0*3420 

0-1875 
0'3420 

Magnesia  

0"1398 

0*1165 

0-1165 

0-1165 

Potash  | 

0-5640 

0-4700 

0-4700 

0-4700 

0-0490 

0-0408 

0-0816 

0'1224 

2-8312 

2-3593 

2-4626 

2-5659 

*  10  cent.  cub.  of  the  solution  contained  exactly  1  decigramme  of  KOPOS 


EXPERIMENTS   ON  VEGETATION   IN   SOLUTIONS.        351 

With  the  exception  of  the  mixture  used  in  Period  V.,  there 
was  added  to  the  others  also  O'l  gramme  of  phosphate  of  iron. 

The  duration  of  these  periods  was  accidental,  depending  on 
fluctuating  meteorological  conditions  of  the  atmosphere,  but  was 
so  far  regulated  that  a  distant  period  was  marked  whenever 
almost  exactly  1  litre  of  water  had  been  exhaled  through  the 
leaves  of  the  plants.  At  this  time  the  remainder  of  the  liquid 
was  drawn  off  for  analysis,  and  the  vessel  filled  with  a  fresh  solu- 
tion. 

In  the  following  the  results  of  the  analysis  are  given  along 
with  the  chief  periods  and  circumstances  of  the  experiments.  In 
the  analytical  results  in  column  A,  is  placed  the  total  quantity  of 
each  acid,  and  salt  received  by  the  plant  fti  that  particular  period ; 
in  column  B,  the  bases  and  acids  found  by  analysis  in  the  remain- 
der of  the  fluid ;  in  column  c,  the  difference  between  A  and  B, 
indicating  the  quantity  of  bases  and  acids  absorbed  by  the  plants. 
Further,  the  relations  of  the  bases  to  each  other,  and  that  of  mag- 
nesia to  sulphuric  acid  (calculated  from  column  A),  are  given ;  the 
quotients  also  express  the  proportions  in  which  these  matters 
were  given  to  the  plants  at  the  beginning  of  the  period.  Imme- 
diately underneath,  indicated  by  "  absorbed,"  are  placed  the  same 
proportions,  calculated  from  column  c,  in  order  to  show  in  what 
ratio  the  plant  has  selected  these  matters  (when  there  does  exist 
a  determinate  power  of  selection). 


SUMMARY     OF     THE   FOOD     GIVEN  ,  TO     A    PLANT    OF     MAIZE 
AND   ASSIMILATED   BY   IT 

I.  Period.  From  May  12  to  June  12. — At  the  commencement 
the  plant  weighed  8  grammes  * ;  and  had  six  leaves  with  a  surface 
of  264  square  centimetres;  water  exhaled  during  the  time  =  1 
litre.  This  period  was  divided  into  three  sections,  in  which  at 
first  dilute  solutions  were  used.  The  mixtures  were  in, — 

Sectiou  I.  Section  II.  Section  III. 

Solution  of  KOP05  .   .        2  cent.  cub.  4  cent.  cub.  6  cent.  cub. 

Normal  solution  A.. ..     100          "  200          "  300          " 

Distilled  water 198          "  96          "  " 

Total  fluid 300          "  300          "  306          " 

Phosphate  of  iron O'l  gramme.          O'l  gramme.          O'l  gramme 


There  were  added  as  the  solution  was  absorbed  by  the  plant, — 

*  The  maize  seed  were  made  to  germinate  in  the  month  of  April  in  well 
washed  sand ;  the  young  plants  weighed  on  the  12th  May,  8  grammes ;  on 
drying  the  residue  weighed  scarcely  more  than  the  seeds. 


352 


APPENDIX  E. 


I.  Section  =    80  cent.  cub.  distilled  water 
II.        "        =  350          "  " 

III.         "        =  570 

1000  cent.  cub.  =  1  litre 

The  residue  from  each  section  =  300  cent,  cub.,  were  united 
and  analysed. 

ABC 
Nitric  acid  ..................     1-2960  ?  ? 

Sulphuric  acid  ..............     0-2970  0-1240  0'1730 

Phosphoric  acid  .............     0-0750  O'OOOO  0-0750 

Lime  .......................     0-4104  0-1480  0'2624 

Magnesia  ...................     0-1398  0-0640  0'0758 

Potash  ..............  „  .......     0-6131  0'2280  0'3851 


2-8313 


0'5640 


0'9713 


In  the  first  of  the  following  lines  are  placed  the  proportions  of 
the  matters  given  to  the  plants,  calculated  from  column  A  ;  in  the 
second,  the  calculations  are  made  from  column  o  :  — 


Absorbed: 


OaO 


MgO 


KO 


S03 


OaO 


MgO 


II.  Period.  From  June  12  to  July  20.  —  At  the  commence- 
ment the  plant  weighed  65  grammes,  and  had  nine  leaves  with  a 
surface  of  648  square  centimetres  ;  water  exhaled  =  1  litre  ;  the 
plant  received  O'l  gramme  of  phosphate  of  iron  suspended  in  the 
water  about  the  roots,  the  roots  became  of  a  reddish  yellow  colour. 


A 

Nitric  acid 1-0800 

Sulphuric  acid 0*2475 

Phosphoric  acid 0-0625 

Lime 0*3420 

Magnesia 0*1165 

Potash 0-5110 

2-3595 

Proportions  of  bases  and  acids, — 
CaO  KO 


B 

? 

0-1704 
0*0000 
0*1912 
0*0860 
0*3120 

0-7596 


C 

? 

0-0771 
0-0625 
0*1508 
0*0305 
0-1990 

0*5199 


Absorbed: 


MgO 


=  5-0; 
' 


CaO 


MgO 


=  a.B 


III.  Period.      From  July  20  to  27.  —  At  the  commencement 
the  plant  weighed  73  grammes,  and  had  eleven  leaves  with  a  sur- 


EXPERIMENTS    ON   VEGETATION    IN    SOLUTIONS.         353 

i 

face  of  720  square  centimetres ;  water  exhaled  =  1  litre ;  to  the 
solution  was  added  0-1  gramme  of  phosphate  of  iron ;  radication 
strong.  This  period  differs  from  the  preceding  in  the  quantity  of 
KOP06  given  being  double. 

ABC 

Nitric  acid 1-0800  ?  V 

Sulphuric  acid 0-2475  0-1716  0-0759 

Phosphoric  acid 0-1250  O'OOOO  0-1250 

Lime 0-3420  0*1440  0*1980 

Magnesia 0-1165  0'0860  0'0305 

Potash...  .  0-5518  0'2160  0'3358 


2-4628  0-6176  0'7652 

Proportions  of  bases  and  acids,  — 


Given:  2.9. 

MgO  CaO 


Absorbed:  -  6-1;  =  1-T; 

CaO 


IV.  Period.  From  July  27  to  August  1.  —  At  the  commence- 
ment the  plant  weighed  147  grammes,  had  eleven  leaves,  with  a 
surface  of  1160  square  centimetres;  water  exhaled  =  1  litre;  to 
the  solution  was  added  O'l  gramme  of  phosphate  of  iron  ;  the 
roots  became  distinctly  reddish  yellow.  The  plants  received  twice 
as  much  KOP05  as  in  the  second  period. 

ABO 

Nitric  acid  ..................  1-0800  ?                     ? 

Sulphuric  acid  ..............  0-2475  0-1374  0-1101 

Phosphoric  acid  .............  0-1250  0-0000  0'1250 

Lime  .......................  0-3420  0-1188  0'2232 

Magnesia  ...................  0-1165  0-0719  0-0446 

Potash...                                   .  0-5518  0*1296  0'4222 


2-4628  0-4617  0-9211 

Proportions  between  bases  and  acids, — 

Given : 
Absorbed : 

To  ascertain  how  far  the  results  from  this  artificial  mode  of 
cultivation  may  be  compared  with  those  produced  under  natural 
circumstances,  maize  of  the  same  kind  was  planted  in  the  garden 
in  the  middle  of  May.  The  latter  were  exposed  to  the  same  at- 
mospheric conditions  as  the  experimental  plants.  On  August  1,  a 
plant  from  the  garden  of  the  same  period  of  vegetation  as  the  ex- 


CaO 

--=2-9; 
=  5-0; 

KO 

1-6; 

1-8; 

S03 

2.  i 

MgO 
CaO 
MgO 

CaO  ~ 
KO 
CaO~ 

MgO 
S03 
MgO 

i 
=  2-3 

354: 


APPENDIX   E. 


perimental  plant,  with  also  fifteen  leaves,  and  visible  male  flowers, 
weighed  1260  grammes,  that  is  to  say,  seven  times  as  much  as  the 
artificially  reared  plant.  The  stem  of  the  garden  plant  from  the 
lower  knot  to  the  summit  of  the  flower-stalk  measured  150  centi- 
metres, being  three  times  the  height  of  the  experimental  plant. 

V.  Period.  From  August  1  to  10. — At  the  commencement  the 
plant  weighed  173  grammes ;  the  stem  was  52  centimetres  high  ; 
in  the  middle  of  the  period  the  plant  had  fifteen  large  fine  green 
leaves,  with  a  surface  of  1420  square  centimetres.  In  this  period 
double  the  quantity  of  water  (2  litres)  was  exhaled,  and  as  the 
older  roots  were  distinctly  reddish  yellow  in  colour,  the  plant  re- 
ceived no  more  phosphate  of  iron,  but  thrice  as  much  phosphate 
of  potash  as  in  the  second  period.  On  August  6  and  7,  the  male 
flower,  consisting  of  seven  single  ears,  was  fully  expanded  from 
the  sheath,  the  stem  was  strong,  and  70  centimetres  high.  On 
August  7,  a  fully  formed  female  flower  appeared ;  on  August  9,  the 
anthers  began  to  shed  their  pollen. 


A 

Nitric  acid 1-0800 

Sulphuric  acid 0-2475 

Phosphoric  acid 0-1875 

Lime 0-3420 

Magnesia 0'1165 

Potash 0-5927 


2'5662 


B 

-) 

0-164:0 
0-0020 
0-1236 
0-0790 
0-1894: 

0-5580 


Proportions  between  bases  and  acids, 
CaO  _  KO 

MgO  "       '   CaO  = 
CaO  KO 


Given : 


Absorbed : 


MgO 


=  5-9; 


CaO 


S09 
MgO 

S03 
MgO 


0-0835 
0-1855 
0-2184 
0-0370 
0-4033 

0'9277 


=  2-1 


-2-3 


As  the  plant  in  this  period  flowered,  and  earlier  experiments 
had  shown  that  maize  dug  up  at  the  period  of  flowering,  and 
placed  in  river  water  furnished  still  ripe  seeds,  and  also  by  the  ad- 
dition of  the  salts  which  the  plant  in  each  period  had  taken  up  in 
proportion  to  its  increase  in  weight  in  the  first  four  periods,  it  ap- 
peared that  it  must  contain  fully  as  much  salts  as  the  plant  in  its 
normal  condition  in  the  field  takes  up,  if  placed  from  this  period 
Dnly  in  distilled  water. 

VI.  Period.  From  August  10  to  16. — At  the  commencement 
the  plant  weighed  255  grammes,  and  had  15  fully  expanded  leaves 
with  a  surface  of  2640  square  centimetres :  2  litres  of  water  were 
exhaled. 

On  August  10,  the  anthers  had  almost  completely  shed  their 
pollen.  The  stem  shot  up  rapidly,  and  on  the  12th  it  measured  to 
the  tip  of  the  flower  1  metre  in  height.  On  the  13th  a  second 


EXPERIMENTS   ON   VEGETATION   IN    SOLUTIONS.        355 

female  flower  appeared,  which  was  surrounded  with  paper  to  pro- 
tect it  from  dust.  Ou  August  16  the  height  of  the  plant  was 
l/l  metre ;  it  did  not  grow  any  more.  The  fruit-bearing  stalk 
was,  on  August  16,  already  2  decimetres  long,  and  had  below  a 
thickness  of  4  centimetres. 

On  August  16  the  water  was  drawn  off  and  analysed. 

Present.  Not  present. 

0'016  gramme  potash.  Sulphuric  acid  (only  indistinct  opales- 

0-008        "        lime.  cence  with  chloride  of  barium). 

O'OOl        "        phosphoric  acid.  Magnesia. 

Iron  and  silicic  acid. 

From  the  circumstance  that  in  this  solution  there  was  no  silicic 
acid,  it  is  plain  that  the  glass  vessel  had  furnished  none  to  the  fluid 
by  decomposition  in  the  course  of  one  to  two  weeks. 

VII.  Period.     From  August  16  to  September  4, — 

Weight  of  plant  on  16  August 280  grammes. 

22  "  at  9  o'clock  a.m.  316 
22  "  "  9  "  p.m.  320 
28  "  "  9  "  "  330  " 

1  Sept.       "  9        "        "     327         " 
4      ,<          «  9        <.        <,     317         « 

From  September  1  the  weight  diminished  by  the  drying  of  the 
leaves,  and  as  this  decrease  was  accidental,  the  plant  was  not 
thenceforward  weighed.  The  leaves  shrivelled.  The  plant  had 
exhaled  3£  litres  of  water  in  the  period.  At  this  time  it  was 
placed  in  a  vessel  containing  1'5  litres  of  water,  to  determine  what 
salts  returned  to  the  water  by  endosmone.  The  water  was  kept 
up  at  the  same  level  by  daily  additions,  and  at  last  was  allowed  to 
exhale  until  the  residue  was  1  litre.  In  this  litre  were  found  0.031 
carbonate  of  lime,  and  0.007  carbonate  of  magnesia.  Both  salts 
were  left  in  the  basin  undissolved  after  evaporation,  and  after 
the  residue  had  been  treated  with  water. 

In  the  water  with  which  the  residue  left  on  evaporation  in  the 
basin  had  been  extracted,  the  following  substances  were  found  in 
solution : — 

0-020    lime  I  together  with  organic  matter  which 

0-0006  phosphoric  acid-<  reduced  a  solution  of  oxide  of  copper 
0*0034  potash  (  and  potash. 

In  this  last  solution  not  a  trace  of  iron,  sulphuric  acid  or  mag- 
nesia was  found.  As  the  preceding  analyses  indicate,  the  solution 
of  nutritive  matters  for  grammes  must  have  the  following  com- 
position : — 

MgOS03  +  4CaON05  +  4KONO5  +  xKOPO5 
(Compare  <  Chem.  Central  Blatt,  1861,'  s.  465,  564,  and  945.) 

*  At  all  periods  the  plants  threw  off  organic  substances,  but  chiefly  in  the 
last  periods. 


356  APPENDIX  E. 


II. — Experiments  of  StoJimann. 

The  experiments  of  Stohmann  agree  in  their  main  results  with 
those  of  Knop.  According  to  these  experiments,  the  maize  plant 
grows  to  full  maturity  if  in  the  beginning  of  May  the  seed  which 
has  germinated  in  water,  and  has  shot  forth  roots,  is  placed  in  a 
solution  containing  the  food  of  maize  in  the  proportions  in  which 
they  exist  in  the  ashes,  if  at  the  same  time  there  has  heen  added 
to  it  so  much  nitrate  of  ammonia  that  to  every  part  of  phosphoric 
acid  in  the  solution  there  are  two  parts  of  nitrogen,  and  if  finally 
it  has  been  diluted  with  distilled  water  to  a  concentration  of  three 
parts  of  solid  matter  per  1000  parts.  The  plants  must  grow  in 
a  sunny  spot,  and  the  water  exhaled  by  the  leaves  must  be  daily 
replaced  by  distilled  water,  and  the  solution  tested  as  to  its  reac- 
tion. The  solution  must  always  react,  slightly  acid,  and  be  main- 
tained in  this  condition  by  the  addition  from  time  to  time  of  a  few 
drops  of  phosphoric  acid.  If  these  conditions  are  fulfilled,  there  is 
no  necessity  for  any  artificial  source  of  carbonic  acid,  but  by  means 
of  the  atmospheric  carbonic  acid  alone  there  are  produced  fully 
formed  plants  which,  under  favourable  circumstances,  attain  a 
height  of  7  feet.* 

The  experiments  of  Stohmann  were  more  especially  directed  to 
the  influence  exercised  on  the  growth  of  the  maize  plant  by  the 
withdrawal  of  one  element  of  food.  In  this  point  the  results  differ 
from  those  of  Knop.  Whilst  in  the  experiments  of  the  latter, 
maize  was  found  to  grow  perfectly  without  silicic  acid,  soda,  or 
ammonia,  Stohmann  made  use  of  silicic  acid  in  all  his  experiments, 
and  found  further  that  by  the  complete  withdrawal  of  ammonia 
and  even  soda  the  plants  grew  quite  well. 

On  withdrawing  ammonia  completely  and  replacing  it  by  nitric 
acid,  Stohmann  found  that  the  plants  grew  perfectly  well  for  the 
first  ten  to  twelve  days,  then  they  became  of  a  pale  yellowish 
green,  and  the  vegetation  proceeded  extremely  slowly. 

If  after  a  month's  vegetation  a  little  ammonia  (in  the  form  of 
nitrate  or  acetate)  was  given  to  the  plants,  they  died  very  quickly. 
Without  this  supply  of  ammonia  the  blanched,  sickly  vegetation 
continued ;  the  plant  did  not  die,  and  yet  it  could  not  be  said  to 
live.t  In  the  experiments  made  without  soda,  it  was  found  that 
the  plant  could  dispense  with  this  substance  at  first,  but  its  pro- 
gress was  soon  arrested  if  the  soda  was  completely  withdrawn. 
The  nitrate  of  lime  of  the  normal  solution  was  in  another  experi- 
ment replaced  by  a  corresponding  quantity  of  nitrate  of  magnesia. 
The  growth  of  the  maize  plant  was  after  a  short  time  much  re- 
tarded, only  a  few  small,  thin  leaves  being  developed.  By  the  ad- 
dition of  a  little  nitrate  of  lime  to  the  growing  plant,  the  most 

*  According  to  Knop  maize  plants  growing  in  a  watery  solution  give  off 
carbonic  acid  continuously  from  their  roots. 

t  Compare  Knop,  '  Chem.  Central  Bl.  1862,'  s.  257. 


EXPERIMENTS   ON    VEGETATION   IN    SOLUTIONS.        357 

remarkable  change  was  however  produced.  Scarcely  five  hours 
elapsed  before  the  growth  of  the  plant,  which  had  been  stationary 
for  four  weeks,  awakened  to  a  new  life,  and  proceeded  from  this 
time  forth  in  the  best  manner  possible.  A  plant  without  the  after 
addition  of  nitrate  of  lime  remained  stationary,  making  no  progress 
whatever :  the  maize  plant,  therefore,  requires  lime  immediately 
after  the  commencement  of  its  growth. 

In  an  experiment  in  which  the  magnesia  was  replaced  by  nitrate 
of  lime,  the  same  result  was  obtained  as  when  lime  was  wanting. 
In  this  case,  also,  the  vegetation  was  very  poor.  A  supply  of  mag- 
nesia in  the  form  of  nitrate,  exerted  here  also  the  most  favourable 
action,  only  the  effect  was  not  so  quickly  produced  as  in  the  case 
of  lime. 

Even  by  the  complete  withdrawal  of  nitric  acid  the  maize 
plant  did  not  grow.  In  these  experiments  it  is  true  the  alkalies, 
as  well  as  the  alkaline  earths,  were  in  part  supplied  in  the  form  of 
sulphates  and  chlorides.  Chlorine  and  sulphuric  acid,  however, 
are  required  only  to  a  limited  extent  in  the  vegetable  organism. 
The  same  holds  good  in  the  experiment  without  nitrogen.  Ac- 
cording to  these  experiments,  therefore,  a  plant  is  not  developed 
if  one  of  its  elements  of  food  is  wanting,  and  the  complete  re- 
placement of  one  element  of  food  by  another  one  similar  to  it,  is 
hence  completely  out  of  the  question,  The  result  may,  however, 
be  different  with  the  reciprocal  partial  replacement  of  similar  ele- 
ments of  food ;  and  Stohmann  is  about  to  take  up  this  question. 

The  form  in  which  the  food  was  supplied  was  the  following.* 
The  silicic  acid  was  always  supplied  in  the  form  of  silicate  of  pot- 
ash ;  the  potash  as  nitrate.  In  the  series  of  experiments  (3)  which 
were  made  without  nitric  acid,  sulphate  of  potash  was  used  in- 
stead of  the  nitrate. 

The  phosphoric  acid  was  used  in  the  form  of  2UaO,  HO,  P0s  + 
24HO ;  in  experimental  series  5,  in  which  soda  was  excluded,  a 
potash  salt  was  used,  2KO,  HO,  PO5,  of  which  a  concentrated  so- 
lution was  prepared,  containing  a  known  quantity  of  potash  and 
phosphoric  acid.  As  the  phosphate  of  soda  contained  more  soda 
than  was  requisite  in  the  composition  of  the  ash,  there  was  thus  in 
the  fluids  in  the  experimental  series  1  to  7  an  excess  of  this  base ; 
at  a  later  period,  a  correspondingly  smaller  quantity  of  phosphate 
of  soda  and  more  of  the  potash  salts  were  employed. 

The  sulphuric  acid  was  in  the  form  of  sulphate  of  magnesia, 
with  the  exception  of  7,  in  which  sulphate  of  ammonia  was  used, 
the  magnesia  required  was  added  in  the  form  of,  nitrate  of  mag- 
nesia. 

The  oxide  of  iron  was  supplied  in  the  form  of  pure  sublimed- 

*  To  form  a  complete  solution  of  all  matters,  and  to  remove  the  alkaline 
reaction,  the  fluid  was  first  properly  diluted  with  water  and  so  much  weak 
hydrochloric  and  later  phosphoric  acid  was  added  as  to  make  the  reaction 
distinctly  feebly  acid. 


358 


APPENDIX  E. 


chloride;  the  lime  as  nitrate,  and  in  the  case  of  3  as  chloride  of 
calcium ;  the  ammonia  as  nitrate,  sulphate,  or  chloride. 

It  was  scarcely  possible  to  avoid  using  a  larger  or  smaller  ex^ 
cess  of  one  or  other  of  the  substances.  This  was  particularly  the 
case  with  soda  and  chlorine.  These  deviations  will  be  best  shown 
in  the  following  tables. 

Experimental 


d 

1 

2 

3 

4 

5 

6 

ai 

B 

7 

Intendec 
composite 

Normal. 

11 

|| 

Without  lii 

o'| 

Potash 

o-.q 

35*9 

52'0 

35'9 

35-9 

35'9 

35  -f) 

35'9 

Soda                 ,  .. 

1-0 

8'0 

8'0 

8'0 

8'0 

I'O 

1-0 

Lime  . 

10'8 

10'8 

10'8 

10-8 

10*8 

10'8 

19'2 

Magnesia 

G'O 

6'0 

6'0 

6'0 

6'0 

6'0 

13'7 

Oxide  of  iron...  .  ,  . 
Sulphuric  acid  .... 
Chlorine  . 

2-3 
5'2 

2-3 
5-2 
19  '7 

2'3 

5'2 

2-3 
26-9 
66'5 

2-3 
26'9 
16'8 

2-3 
5-2 

2-3 

5-2 
3-1 

2-3 
5-2 

Phosphoric  acid.  .  . 
Silicic  acid        .   . 

9-1 

28'5 

9-1 

28'5 

9-1 

28'5 

9-1 

28*5 

9-1 

28*5 

9-1 

28-5 

9-1 

28'5 

9-1 
28'5 

Nitrogen     .  .   . 

18'2 

18'2- 

18'2 

18'2 

18'2 

18'2 

1S'2 

Summary  of  the  weights  of  the  crops. 


Experimental 
series. 

Plants. 

Parts  of  plants. 

Dry  substances. 

Amount  of  ash. 

Amount  of  ash. 

^3 

a 

tj 

o 

Proportion  of 
the  weight 
of  the  seed  to 
that  of  the  crop 
after  deduction 
of  the  ash. 

From 

Roots  

grms. 
10-36  "I 

grms. 

per  ct. 

grms. 

the 

52*39  1 

srar- 

42-39  f 

15'24 

11-4 

— 

— 

y 

den. 

"       of  the  head. 
G'raius               .   . 

28-51  J 
190-14 

3'49 

rs 

3  heads 

22-66 

0-54 

2-4 

Entire  plant          .  . 

346-45 

19-20 

5-5 

327-25 

1  •  3147 

1 

A 

Roots 

3-92"! 

Stem  . 

9'67  1 

Leaves 

11-79  f 

3*97 

13-1 

— 

— 

"      of  heads  .  .  . 
Head  with  grain  .  . 
Entire  plant  

4-91  J 
34-09 
64'38 

0-82 
4-79 

2-4 
7'5 

59-59 

1  :  573 

B 

Straw  

27'36 

4-35 

15-9 

Heads     

4-24 

0-14 

3-4 



Grains  

24-57 

0-56 

2-3 

__ 

Entire  plant  ..... 

56-17 

5-05 

8-9 

51-12 

1  :491 

EXPERIMENTS   ON   VEGETATION   IN    SOLUTIONS. 


359 


of  the  weights  of  the  crops. — (Continued.) 


3 

to 

1 

1 

1 

Proportion  of 
the  weight 

ii 

^    CO 

1 

Parts  of  plants. 

1 

0 

1 

"c 

g 

g 
°5 

of  the  seed  to 
that  of  the  crop 
after  deduction 

I 

fe 

a 

g 

H 

of  the  ash. 

w 

Q 

< 

O 

grms. 

grms. 

per  ct. 

grins. 

2. 

C 
D 

Entire  plant  

55-52 
62-44 

5-94 
6-49 

10-7 
10-4 

49-58 
55-95 

1  :477 
1  :  538 

A—  C 

"           "      

1-19 

— 

— 

— 

— 

D 

(<           <t 

2  '39 

0-54 

OO»Q 

res 

1  :  18 

3 

A—  B 

«           « 

0-204 

4 

A 

Roots  

0-45 

o-io 

22-8 

_ 

Stem  and  leaves.  .  . 

1-03 

0-17 

16-7 





Entire  plant  

1-48 

0-27 

18-2 

1-21 

1     12 

C 

•          tt 

10'90 

0'92 

8*5 

9'98 

1     96 

D 

( 

39-48 

5-57 

14-1 

33-91 

1     326 

5. 

A 

i 

49-63 

5-21 

10-5 

44-42 

1    427 

T> 

^ 

32-31 

3'36 

10'4 

28'95 

1    278 

P 

A 

( 

0'30 

' 

( 

84-30 

8'22 

9-75 

76-08 

1    731 

7 

A 

4 

0-82 

0'18 

21'4 

0*64 

1    6 

B      C 

i 

6'01 

0'82 

13  '7 

5*19 

1     50 

REMARKS    ON   THE  SUMMARY  OF  THE  WEIGHTS  OF  THE  CROPS. 

I.  Plants  A,  B,  c,  and  D  grew  in  normal  solutions.    Plants  A  and 
B  were  placed  in  the  solution  on  July  1,  and  plant  A  was  gathered 
on  September  10,  fully  ripened ;  its  total  height  was  202  centi- 
metres.    The  plant  from  the  garden  soil  with  which  it  was  com- 
pdred  was  of  middle  size.     Plant  B  gathered  on  September  27, 
was  fully  grown,  and  had  a  height  of  127"  centimetres.     Plants  c 
and  D  were  placed  in  the  normal  solution  on  June  10,  they  did 
not  attain  their  full  growth ;  both  were  gathered  on  October  28. 

II.  Commencement  of  experiment  in  solutions  without  ammonia 
on  June  10.— A  and  B  received  on  July  12  a  supply  of  0-2  gramme 
nitrate  of  ammonia ;  on  July  23  they  were  placed  in  a  fresh  solution, 
to  which  was  added  0*2  gramme  acetate  of  ammonia ;  both  plants 
died  on  July  31.     Plants  c  and  D  received  normal  solution  on 
August 4,  which  was  neutralised  with  phosphoric  acid;  o  died  on 
August  9,  D  recovered  somewhat,  but  remained  sickly  till  gathered 
on  September  27. 

III.  Experiments  without    nitric   acid. — Commencement   on 
June  10 ;  rapid  decay  of  the  plants ;  by  July  1  A  and  B  were  al- 
ready dead. 

IV.  Experiments  without  nitrogen. — Commencement  on  June 
10.    In  the  first  week  the  growth  was  excellent,  but  in  the  second 


360  APPENDIX   F. 

week  it  came  to  a  stand.  A  lived  till  gathered  on  September  27 ; 
height  15  centimetres,  length  of  roots  82  centimetres.  Plants  o 
and  D  received  on  July  1-1  each  0'2  gramme  nitrate  of  ammonia, 
and  on  July  17,  also,  the  same  quantity.  The  influence  of  this 
salt  was  rapidly  visible.  On  August  4,  c  and  D  received  normal 
solution.  Plant  c  was  gathered  on  September  27,  height  75  centi- 
metres. Plant  D,  gathered  on  November  15,  was  in  a  healthy  state, 
and  had  attained  a  height  of  120  centimetres. 

V.  Experiments  without  soda. — Commencement  June  10.    The 
early  vegetation  was  very  luxuriant ;  in  the  end  of  July,  however, 
the  plants  were  not  progressing.    On  August  4,  the  plants  received 
normal  solution ;  two  died,  but  A  and  B  made  further  progress. 
A  and  B  were  gathered  on  October  30,  height  of  A,  205  centi- 
metres ;  B  stunted. 

VI.  Experiments    without  lime. — Commencement   June   10. 
Plant  A  had  reached  a  height  of  2  centimetres  on  July  17;  but 
made  no  further  progress.     B  received  on  July  1,  O'l  gramme  lime 
in  the  form  of  nitrate,  and  on  August  4,  normal  solution,  vigor- 
ous growth.     It  had  on  November  15  four  stems  respectively  107, 
95,  75,  70  centimetres  high,  which  were  covered  with  leaves,  and 
had  eight  well  developed  heads  of  fruit. 

VII.  Experiments  without    magnesia. — Commencement   June 
10.     Progress  as  in  Experiment  VI.,  and  gathered  as  it  was  mak- 
ing no  visible  progress.     B  and  o  received  on  July  17,  O'l  gramme 
magnesia,  and  on  August  4  normal  solution,  gathered  September 
27;  height  of  B,  23  centimetres;  of  c,  42  centimetres.    Both  had 
male  flowers  without  pollen,  and  no  female  flowers. 

On  comparing  his  experimental  plants  with  those  which  grew 
in  the  ground,  both  in  respect  to  weight  of  the  crop  and  to  amount 
of  ash  and  its  composition,  Stohmann  concluded  that  we  may  in- 
deed convert  a  plant  of  maize  into  a  water-plant,  but  that  maize 
cannot  grow  in  a  normal  condition  in  solutions  of  its  food.  Fur- 
ther, his  experiments  showed  in  a  positive  manner  that  the  soil 
played  a  determinate  part  in  the  nutriment  of  plants — absorption 
of  alkalies — and  that  plants  in  the  absorption  of  their  food  must 
themselves  take  an  active  part  (compare  Henneberg's  '  Journal  fiir 
landwirthschaft,  1862,'  s.  1.  and  'An.  der  Chem.  und  Pharm.,'  bd. 
cxxi.  s.  285). 


APPENDIX  F  (pp.  114,  115). 

EXPERIMENTS    ON   THE    GROWTH    OF   BEANS    IN    POWDERED 
TURF. 

To  complete  the  experiments  on  vegetation  described  at  page 
112,  the  results  of  the.  entire  crops  are  now  given  in  the  following 
table :  - 


EXPERIMENTS  ON  THE  GROWTH  OF  BEANS. 


361 


Dry  substance  of  the  bean  plants  in  grammes. 


L  Pot, 

fully 
saturated. 

II.  Pot, 

half 
saturated. 

III.  Pot, 
quarter 
saturated. 

IV.  Pot, 
pure 
turf. 

Seed  

93-240 

66-127 

50-463 

7-069 

Shell  

25-948 

18-393 

13-658 

2-631 

Leaves  

19-420 

15-797 

12-477 

1-979 

Stem  

26-007 

20-107 

15-710 

5-676 

Roots  

58-399 

36-368 

25-411 

3-063 

Total  weight  

223-014 

156-792 

117-719 

20-418 

These  numbers  completely  confirm  the  conclusions  drawn  from 
the  weight  of  the  seeds  alone.  If  the  crop  from  the  pure  turf  be 
taken  as  unity,  the  weights  of  the  entire  crops  bear  the  following 
proportions — 

1:5-7:  7'7  :  10-9 

or  if  the  weight  of  the  crop  in  the  \  saturated  turf  be  called  2,  and 
that  of  the  £  and  fully  saturated  turf  be  compared  with  it,  the  fol- 
lowing proportions  are  found — 

2:2-7:  3'8 

If  the  weight  of  the  crop  furnished  by  the  pure  turf  be  sub- 
tracted from  each  of  the  others,  and  the  weight  of  the  crop  in  the 
\  saturated  turf  be  taken  at  2,  then  the  crops  in  the  \  and  fully 
saturated  turfs  bear  the  following  proportions  to  it — 

2  :  2-8  :  4'2 


APPENDIX  G  (page  229). 

Extract  from  the  Report  to  the  Minister  of  Agriculture  at  Berlin, 
on  Japanese  Husbandry ;  by  DE.  H.  MAKON,  Member  of  the 
Prussian  East  Asiatic  Expedition. 

SECTION  I. 

SOIL  AND   MANUEING. 

The  Japanese  empire  stretches  from  the  30th  to  the  45th  de- 
gree of  north  latitude.  The  average  temperature  and  distribution 
of  heat  constitute  a  climate  embracing  all  the  gradations  between 
those  of  central  Germany  and  of  Upper  Italy.  A  solitary  tropical 
palm,  not  fully  developed,  grows  by  the  side  of  the  northern  pine, 
1G 


362  APPENDIX   G. 

rice  and  cotton  along  with  buckwheat  and  barley.  Everywhere 
on  the  chains  of  hills,  which  cover  the  whole  country  like  an  ir- 
regular fine  network,  the  pine  predominates,  stamping  upon  the 
landscape  that  homely  northern  character,  which  affords  so  cheer- 
ing a  sight  to  the  northern  traveller,  who  reaches  these  shores  after 
having  passed  through  the  hot  and  luxuriant  regions  of  the  tropics. 
In  the  valleys,  on  the  other  hand,  the  burning  south  holds  sway, 
covering  the  ground  with  a  rich  vegetation  of  rice,  cotton,  yams, 
and  sweet  potatoes.  Hundreds  of  footpaths  and  small  ravines  lead 
to  charming  transitions  between  pine  and  cotton,  hill  and  dale ; 
everywhere  there  is  a  gay  medley  of  laurels,  myrtles,  cypresses, 
and  above  all,  shining  camellias. 

The  land  is  of  volcanic  origin,  and  the  entire  surface  belongs 
to  the  tufa  and  the  diluvium  formation.  The  soil  on  the  hills  con- 
sists of  an  extremely  fine,  yet  not  over  fat  brown  clay ;  whereas 
that  of  the  valleys  is  throughout  the  country,  with  some  trifling 
modifications,  of  a  black,  loose,  and  deep  garden  mould,  which 
upon  trial  in  different  places  I  found  extended  to  a  depth  of  12  to 
15  feet,  being  throughout  of  the  same  quality,  though  somewhat 
more  compact  in  the  deeper  layers.  An  impermeable  stratum  of 
clay  probably  underlies  this  arable  crust.  As  the  clay  strata  of  the 
mountains,  in  consequence  of  the  frequent  and  copious  falls  of  rain, 
give  rise  to  a  multitude  of  springs,  which  are  everywhere  at  hand, 
and  may  thus  easily  and  without  any  great  skill,  be  turned  to  ac- 
count for  the  purpose  of  irrigation ;  so  the  impermeability  of  the 
stratum  underlying  the  surface  soil  in  the  valleys  enables  the  Jap- 
anese husbandmen  to  turn  the  soil  a^  pleasure  into  a  swamp,  for 
the  cultivation  of  rice. 

Whichever  way  one  may  feel  inclined  to  decide  the  question, 
whether  the  present  fruitfulness  of  the  soil  is  simply  the  artificial 
product  of  cultivation  continued  for  a  period  of  several  thousand 
years,  or  whether  this  fertility  existed  from  the  beginning,  making 
this  people  love  and  cherish  the  labours  of  agriculture,  this  much 
must  be  granted,  at  all  events,  that  the  clay  of  the  diluvium,  the 
mild  climate,  and  abundance  of  water,  afforded  all  the  conditions, 
and  the  most  convenient  means,  for  a  thriving  cultivation.  All 
these  advantages  have  been  most  carefully  turned  to  account  by 
an  industrious,  ingenious,  and  sober  people ;  and  husbandry  in 
Japan  has  become  a  truly  national  occupation.  The  Japanese 
have  thoroughly  mastered  the  difficult  task  of  maintaining  agricul- 
ture in  a  state  of  the  highest  perfection,  although  its  pursuit  is  en- 
tirely in  the  hands  of  peasants  and  yeomen,  who  take  rank  in  the 
sixth  and  last  but  one  class  of  the  social  scale,  and  no  Japanese 
gentleman  is  a  farmer.  There  are  no  agricultural  institutions  for 
instruction  in  husbandry,  no  agricultural  societies,  no  academies, 
no  periodical  press  to  spread  the  teachings  of  science.  The  son 
simply  learns  from  the  father ;  and  as  the  father  knows  quite  as 
much  as  his  grandfather  and  great  grandfather  before  him,  so  he 


JAPANESE   HUSBANDRY.  363 

pursues  exactly  the  same  system  of  husbandry  as  any  other  peasant 
in  any  other  part  of  the  empire  ;  but  it  is  a  matter  of  perfect  in- 
difference where  the  young  agriculturist  learns  his  business.  The 
young  pupil  in  husbandry  will  always  be  able  to  master  a  certain 
small  amount  of  information  which  the  experience  of  ages  has 
shown  to  be  true,  so  that  it  may  be  looked  upon  as  positive  knowl- 
edge, and  a  sort  of  hereditary  heirloom. 

I  must  confess  that  I  experienced  a  feeling  of  deep  humiliation 
on  many  occasions,  when  with  this  simple  knowledge,  and  the  safe 
and  uncontented  practical  application  of  it  in  husbandry  before  my 
eyes,  I  thought  of  home.  We  boast  that  we  are  a  civilized  nation ; 
in  our  land  men  of  the  highest  intellectual  attainments  devote 
their  best  energy  to  the  improvement  of  agriculture;  we  have- 
everywhere  agricultural  institutions  and  agricultural  societies, 
chemical  laboratories  and  model  farms,  to  increase  and  diffuse  the 
knowledge  of  husbandry.  And  yet  how  strange  that,  despite  all 
this,  we  still  go  on  disputing,  often  so  vehemently  and  acrimo- 
niously, about  the  first  and  most  simple  scientific  principles  of  agri- 
culture ;  and  that  those  who  earnestly  search  after  truth  are  forced 
to  admit  the  infinite  smallness  of  their  positive  and  undisputed 
knowledge !  How  strange  also  that  even  this  trifling  amount  of 
positive  knowledge  has  as  yet  found  so  little  application  in  prac- 
tice! 

Among  the  great  questions  which  still  remain  in  dispute  with 
us,  whilst  in  Japan  they  have  long  since  been  settled  in  the  labo- 
ratory of  an  experience  extending  over  thousands  of  years,  I  must 
mention  as  the  most  important  of  all,  that  of  manuring.  The  edu- 
cated sensible  farmer  of  the  old  world,  who  has  insensibly  come 
to  look  upon  England,  with  its  .meadows,  its  enormous  fodder 
production  and  immense  herds  of  cattle,  and  in  spite  of  these  with 
its  great  consumption  of  guano,  ground  bones,  and  rape-cake,  as 
the  beau  ideal  and  the  only  possible  type  of  a  truly  rational  sys- 
tem of  husbandry,  would  certainly  think  it  a  most  surprising  cir- 
cumstance to  see  a  country  even  much  better  cultivated,  without 
meadows,  without  fodder  production,  and  even  without  a  single 
head  of  cattle,  either  for  draught  or  for  fattening,  and  without  the 
least  supply  of  guano,  ground  bones,  saltpetre,  or  rape-cake.  This 
is  Japan. 

I  cannot  help  smiling  when  I  remember  how,  on  my  passing 
through  England,  one  of  the  great  leaders  of  agriculture  in  that 
country,  pointing  to  his  abundant  stock  of  cattle,  endeavoured  with 
an  authoritative  air  to  impress  upon  my  mind  the  following  ax- 
ioms, as  the  great  secret  of  true  wisdom: — 'The  more  fodder,  the 
more  flesh ;  the  more  flesh,  the  more  manure ;  the  more  manure, 
the  more  grain ! '  The  Japanese  peasant  knows  nothing  of  this 
chain  of  conclusions;  he  simply  holds  fast  to  one  indisputable 
axiom,  viz.  without  continuous  manuring  there  can  be  no  continut 
ous  production.  A  small  portion  of  what  I  take  from  the  soil  is 


364  APPENDIX   G. 

replaced  by  nature  (the  atmosphere  and  the  rain),  the  remainder  I 
must  restore  to  the  ground ;  the  manner  in  which  this  is  done  is  a 
matter  of  indifference.  That  the  produce  of  the  land  has  first 
to  pass  through  the  human  body  before  it  can  be  returned  to  the 
soil,  is,  as  far  as  manuring  is  concerned,  simply  a  necessary  evil, 
which  always  involves  a  certain  loss.  As  to  the  intermediate  stage 
of  cattle  feeding,  which  we  deem  so  requisite  in  our  system,  the 
Japanese  farmer  cannot  at  all  see  its  necessity.  He  argues  in  his 
way  that  it  must  cost  a  great  deal  of  unnecessary  and  expensive 
labour  to  have  the  produce  of  the  field  first  eaten  by  cattle,  so 
troublesome  and  expensive  to  breed,  and  that  this  system  must  in- 
volve more  considerable  loss  of  matter  than  his  own.  How  much 
.more  simple  it  must  be  to  eat  the  corn  yourself,  and  to  produce 
your  own  manure !  Far  from  me  be  it,  however,  upon  the  ground 
of  the  so  widely  differing  results  to  which  the  developement  of 
agriculture  has  led  in  the  two  lands,  to  pass  judgement  upon  our 
system  of  husbandry,  and  to  exalt  unduly  that  of  the  Japanese  by 
attributing  superior  intelligence  to  that  nation.  Circumstances 
have  brought  about  the  results  in  question,  and  the  following  more 
especially  have  exercised  a  decided  influence  in  the  matter.  The 
religious  belief  of  the  two  great  sects  in  Japan,  the  Sintoists  and 
the  Buddhists,  forbids  the  eating  of  flesh,  and  not  alone  of  flesh, 
but  of  everything  derived  from  animals  (milk,  butter,  cheese)  ;  this 
prohibition,  of  course,  disposes  of  one  of  the  principal  objects  for 
which  cattle  are  bred.  Even  sheep,  if  kept  for  the  wool  alone, 
would  not  pay,  as  our  farmers  begin  to  find  out  even  in  Germany. 

The  very  limited  area  of  the  homesteads  in  Japan  also  makes 
the  maintaining  of  cattle  superfluous.  The  smallness  of  the  farms 
must  not  be  attributed,  however,  to  any  excessive  tendency  to  sub- 
division of  landed  property,  but  to  the  fact  that  the  land  belongs 
to  the  great  princes  or  Daimios  of  the  country,  Vho  have  bestowed 
it  in  fee  upon  the  lower,  nobility.  The  latter,  again,  being  pre- 
cluded by  the  institutions  of  the  country  from  farming  their  own 
estates,  have  parcelled  the  land  out,  apparently  from  time  imme- 
morial, on  perpetual  leases,  among  the  peasantry  of  the  country. 
The  size  of  these  farms  varies  from  two  to  five  acres  ;  the  limita- 
tion having  been  most  likely  determined  either  by  their  natural 
position,  or  from  the  course  of  some  brook  or  rivulet.  Now,  as 
this  limited  area  is  intersected  moreover  by  drains  and  ditches,  it 
will  be  readily  seen  that  there  is  hardly  a  plot  of  ground  to  be 
found  where  the  use  of  beasts  of  burden  might  be  profitably  had 
recourse  to. 

Now,  with  us  matters  are  very  different  in  these  respects.  We 
have  a  notion  that  we  could  not  possibly  exist  in  health  and  vigour 
without  a  considerable  consumption  of  meat,  although  we  have 
the  fact  constantly  before  our  eyes,  that  our  labourers,  who  assur- 
edly require  as  much  strength  as  any  other  class  of  society,  are, 
for  the  most  part,  involuntary  Buddhists.  Our  farms  are  always 


JAPANESE   HUSBANDRY.  365 

sufficiently  large  to  preclude  the  notion  of  working  them  by  hand, 
even  leaving  out  of  consideration  the  important  circumstance  that 
the  price  of  labour  is  rather  too  high,  in  proportion  to  the  value  of 
the  produce,  to  admit  of  such  a  system  of  farming.  But  that  the 
culture  of  the  soil  is  everywhere  in  the  world  in  direct  ratio  to  the 
division  of  the  land  is  a  well-established  fact,  of  which  the  reality 
and  significance  are  made  most  clearly  apparent  to  the  traveller 
who  passes  from  the  north  of  Germany  to  Japan,  via  England. 

The  only  manure-producer,  therefore,  in  Japan  is  man;  and 
we  need  not  wonder  that  the  greatest  care  should  be  bestowed  in 
that  country  upon  the  gathering,  preparing,  and  applying  his  ex- 
crements. Now,  as  their  entire  course  of  proceeding  contains 
much  that  is  highly  instructive  for  us,  I  consider  it  my  duty  to 
give  as  detailed  a  description  of  it  as  possible,  even  at  the  risk  of 
offending  the  delicate  feelings  of  the  reader. 

The  Japanese  does  not  construct  his  privy  as  we  do  in  Ger- 
many, in  some  remote  corner  of  the  yard,  with  half- open  rear, 
giving  free  admission  to  wind  and  rain ;  but  he  makes  it  an  essen- 
tial part  of  the  interior  of  his  dwelling.  As  he  ignores  altogether 
the  notion  of  a  '  seat,'  the  cabinet,  which,  as  a  general  rule,  is  very 
clean,  neat,  and,  in  many  cases,  nicely  papered  or  painted  and  var- 
nished, has  a  simple  hole  of  the  shape  of  an  oblong  square  running 
across  and  opposite  to  the  entrance  door,  and  serving  to  convey  the 
excrements  into  the  lower  space.  Squatting  over  this  hole,  with 
his  legs  astride,  the  Japanese  satisfies  the  call  of  nature  with  the 
greatest  cleanliness.  I  never  saw  a  dirty  cabinet  in  Japan,  even  in 
the  dwelling  of  the  very  poorest  peasant.  It  appears  to  me  that 
there  is  something  very  practical  in  this  form  of  construction  of  a 
closet.  We,  in  Germany,  construct  privies  over  our  dung-holes, 
and  behind  our  barns,  for  the  use  of  our  farm-servants  and  labour- 
ers, and  provide  them  with  seats  with  round  holes.  With  even 
only  one  aperture,  it  is  too  often  found  that  after  a  few  days'  use 
they  look  more  like  pigstyes  than  closets  for  the  use  of  man,  and 
this  simply  because  our  labourers  have  a  decided,  perhaps  natural, 
predilection  for  squatting.  The  construction  of  the  Japanese  privies 
shows  how  easy  it  would  be  to  satisfy  this  predilection. 

To  receive  the  excrements,  there  is  placed  below  the  square 
hole  a  bucket  or  tub,  of  a  size  corresponding  to  it,  with  projecting 
ears,  through  which  a  pole  can  be  passed  to  carry  the  vessel.  In 
many  instances  a  large  earthen  pot,  with  handles,  is  used,  for  the 
manufacture  of  which  the  Japanese  clay  supplies  an  excellent  mate- 
rial. In  some  rare  instances  in  the  towns,  I  found  a  layer  of  chop- 
ped straw  or  chaff  at  the  bottom  of  the  vessel,  and  occasionally 
also  interspersed  among  the  excrements,  a  proceeding  which,  if  I 
mistake  not,  has  of  late  been  recommended  also  in  Germany.  As 
soon  as  the  vessel  is  full,  it  is  taken  out  and  emptied  into  one  of 
the  large  dung- vessels.  These  are  placed  either  in  the  yard  or 
in  the  field.  They  are  large  casks  or  enormous  stoneware  jars,  in 


366  APPENDIX   G. 

capacity  of  from  8  to  12  cubic  feet,  let  into  the  ground  nearly  to 
tlie  brim.  It  is  in  these  vessels  that  the  manure  is  prepared  for 
the  field.  The  excrements  are  diluted  with  water,  no  other  addi- 
tion of  any  kind  being  made  to  them,  and  stirred  until  the  entire 
mass  is  worked  into  a  most  intimately  intermixed  fine  pap.  In 
rainy  weather,  the  vessel  is  covered  with  a  moveable  roof  to  shield 
it  from  the  rain ;  in  dry  weather  this  is  removed,  to  allow  the 
action  of  the  sun  and  wind.  The  solid  ingredients  of  the  pap  grad- 
ually subside,  and  fermentation  sets  in ;  the  water  evaporates.  By 
this  time  the  vessel  in  the  privy  is  again  ready  for  emptying.  A 
fresh  quantity  of  water  is  added,  the  whole  mass  is  again  stirred 
and  most  intimately  mixed  together,  in  short,  treated  exactly  like 
the  first  emptying.  The  same  process  is  repeated,  until  the  cask 
or  pan  is  full.  After  the  last  supply  of  excrements,  and  thorough 
mixing,  the  mass  is  left,  according  to  the  state  of  the  weather,  for 
two  or  three  weeks  longer,  or  until  it  is  required  for  use ;  but  under 
no  circumstance  is  the  manure  ever  employed  in  the  fresh  state. 

THIS  ENTIRE  OOUESE  OF  PROCEEDING  CLEARLY  SHOWS  THAT  THE  JAP- 
ANESE ARE  NO  PARTISANS  OF  THE  NITROGEN  THEORY,  AND  THAT  THEY 
ONLY  CARE  FOR  THE  SOLID  INGREDIENTS  OF  THE  DUNG.  They  leave 

the  ammonia  exposed  to  decomposition  by  the  action  of  the  sun,  and 
its  volatilisation  by  the  wind,  but  take  the  greater  care  to  shield  the 
solid  ingredients  from  being  wasted  or  swept  away  by  rain,  &c.  As 
the  peasant,  however,  pays  his  rent  to  his  landlord  not  in  cash,  but 
in  a  certain  stipulated  percentage  of  the  produce  of  his  fields,  he 
argues  quite  logically  that  the  supply  of  manure  from  his  privy 
must  necessarily  be  insufficient  to  prevent  the  gradual  exhaustion 
of  the  soil  of  his  farm ;  notwithstanding  the  marvellous  richness 
of  the  latter,  and  in  spite  of  the  additional  supply  of  manuring 
matter  derived  from  the  water  of  the  brook  or  canal  from  which 
he  takes  his  material  for  irrigation.  He  places,  therefore,  wher- 
ever his  field  is  bordered  by  public  roads,  footpaths,  &c.,  casks  or 
pots  buried  in  the  ground  nearly  to  the  rim,  urgently  requesting 
the  travelling  public  to  make  use  of  the  same.  To  show  how 
universally  the  economical  value  of  manure  is  felt  and  appreciated 
in  all  classes  of  society  in  Japan,  from  the  highest  to  the  lowest,  I 
need  simply  state  the  fact  that,  in  all  my  wanderings  through  the 
country,  even  in  the  most  remote  valleys,  and  in  the  homesteads 
and  cottages  of  the  very  poorest  of  the  peasantry,  I  never  could 
discover,  even  in  the  most  secret  and  secluded  corners,  the  least 
trace  of  human  excrements.  How  very  different  with  us,  in  Ger- 
many, where  it  may  be  seen  lying  about  in  every  direction,  even 
close  to  privies ! 

I  need  not  mention  that  the  manure  thus  left  by  benevolent 
travellers  is  treated  exactly  in  the  same  way  as  the  family  manure. 

But  the  excrements  of  the  peasant  contain  also  some  other 
matter,  which  has  not  been  derived  from  the  soil  of  his  fields,  and 
which  may  be  said  to  represent  an  additional  importation  of  ma- 


JAPANESE   HUSBANDRY.  367 

nure.  The  river,  brooks,  and  canals,  and  the  numerous  little 
bays,  abound  in  fish,  which  the  religion  of  the  Japanese  permits 
him  to  eat,  a  permission  of  which  he  most  largely  avails  himself. 
Fishes,  crabs,  lobsters,  and  snails  are  eaten  in  quantities,  and  these 
ultimately  afford  a  most  valuable  item  of  contribution  to  the  privy, 
and  consequently  to  the  fertilising  field-manure. 

The  Japanese  farmer  prepares  also  compost.  •  As  he  keeps  no 
cattle  to  turn  his  straw,  &c.,  into  manure,  he  is  forced  to  incorpo- 
rate this  part  of  his  produce  with  the  soil  without  '  animalisation.'- 
The  method  pursued  to  effect  this  object  consists  simply  in  the 
concentration  of  the  materials.  Chaff,  chopped  straw,  horse-dung, 
excrement  gathered  in  the  highways,  tops  and  leaves  of  turnips, 
peelings  of  yams  and  sweet  potatoes,  and  all  the  offal  of  the  farm, 
are  carefully  mixed  with  a  little  mould,  shovelled  up  in  small 
pyramidal  heaps,  moistened  and  covered  with  a  straw  thatch.  I 
often  saw  also  in  this  compost  heaps  of  shells  of  mussels  and 
snails,  with  which  most  of  the  rivulets  and  brooks  abound,  and 
which,  in  all  parts  close  to  the  seashore,  may  be  obtained  in  any 
quantities.  The  compost  heaps  are  occasionally  moistened  and 
turned  with  the  shovel,  and  thus  the  process  of  decomposition 
proceeds  rapidly,  under  the  powerful  action  of  the  sun.  I  have 
also  often  seen  the  shorter  process  of  reduction  by  fire  resorted  to 
when  there  was  plenty  of  straw,  or  where  the  manure  was  required 
for  use  before  it  could  be  got  ready  by  the  fermentation  process. 

The  half-charred  mass  was,  in  such  cases,  in  so  far  as  my  own 
observation  enabled  me  to  judge,  strewed  directly  on  the  seed 
sown  in  the  ground. 

I  think  the  treatment  of  this  compost  is  another  proof  that  the 
Japanese  farmer  does  not  care  for  the  azotised  matters,  and  that 
he  strives  to  destroy  all  organic  substances  in  his  manure  before 
making  use  of  it.  The  great  object  of  the  Japanese  farmer  in  all 
this  is  to  turn  Ms  manure  to  account  as  promptly  as  possible. 

To  attain  this  end,  besides  preparing  his  manures  in  the  man- 
ner described,  he  has  recourse  also  to  the  following  means : — 

1.  He  applies  his  manures,  and  particularly  his  chief  manure 
derived  from  his  privy,  invariably  as  much  as  possible  in  the  liquid 
form. 

2.  He  knows  no  other  mode  of  manuring  than  that  of  top- 


When  he  wishes  to  sow,  the  land  is  laid  in  furrows,  in  the  way 
to  be  more  fully  described  hereafter,  and  the  seed  is  strewn  by 
hand,  and  covered  with  a  thin  and  even  layer  of  compost,  over 
which  liquefied  and  very  dilute  privy  manure  is  poured.  The 
manure  is  diluted  in  the  buckets  in  which  it  is  carried  from  the 
preparing  tubs  or  pots  to  the  seed  furrow,  as  this  is  the  only  way 
to  ensure  uniform  intermixing  of  the  materials.  As  this  manure 
has  fully  fermented,  it  may  without  danger  be  brought  into  imme- 
diate contact  with  the  seed,  and  thus  materially  assist  the  first 
radication. 


368  APPENDIX   G. 

It  may  be  that  this  Japanese  system  of  manuring  cannot  as  yet 
be  introduced  into  Europe  in  its  integrity.  But  with  such  excel- 
lent results  to  show  for  their  proceedings,  we  might  surely  take  a 
few  lessons  from  these  old  practical  men,  and  employ  them  with 
such  modifications  as  our  social  relations  require.  At  all  events 
we  might  adopt  in  principle  the  following : — 

1.  The  greatest  possible  concentration  of  manures,  which  must 
necessarily  lead  also  to  a  material  reduction  of  cost.    When  I 
stated  that  the  Japanese  does  not  trouble  himself  about  the  azo- 
tised  matters  in  his  manures,  and  that  his  land  is,  notwithstanding, 
in  a  most  flourishing  state  of  culture,  this  is  no  proof,  however, 
that  it  might  not  even  le  better,  perhaps,  to  endeavour  to  fix  the 
nitrogen  too.     If  a  more  practical  system  can  be  devised,  of  which 
however  I  have  my  doubts,  combining  the  advantage  of  both,  so 
much  the  better!     But  till  something  better  is  discovered,  we 
might  surely  adopt  that  which  experience  has  proved  to  be  good. 

2.  Top-dressing,  which  is  of  course  necessarily  connected  with 
cultivation  in  drills  or  furrows. 

3.  Liquid  manuring :  not  to  the  extravagant  extent,  however, 
in  which  it  was  sought  to  be  carried  out  in  England,  but  in  accord- 
ance with  the  present  condition  of  German  agriculture. 

4.  Manuring  with  every  crop. 

The  Japanese  never  cultivates  a  crop  without  manuring  it,  but 
he  gives  each  crop  or  seed  exactly  as  much  and  no  more  manure 
than  is  required  for  its  full  developement.  He  does  not  care  about 
enriching  the  soil  for  future  crops.  What  he  demands  is  simply  a 
full  crop  in  return  for  each  sowing.  How  often  do  we  hear  our 
farmers  talk  about  this  manure  being  preferable  to  that  manure  on 
account  of  its  fertilising  action  being  '  more  lasting;'  yet  with  all 
our  wise  provision  for  the  future,  how  far  are  we  now  behind  the 
Japanese,  who  seem  to  look  always  to  the  next  harvest  only!  As 
they  manure  for  each  fresh  crop,  and  the  term  '  fallow '  in  our  ac- 
ceptation is  entirely  unknown  to  them,  they  are  forced  to  distrib- 
ute their  yearly  production  of  manure  equally  over  the  entire  area 
of  their  land,  which  can  be  accomplished  only  by  sowing  in  drills 
or  furrows,  and  by  top-dressing. 

The  contrast  between  this  rational  system  and  the  profuse  ap- 
plication of  our  long  straw  manure  over  the  whole  surface  of  the 
field  is  truly  glaring. 

I  may  also  add  here  that  the  manure  in  the  Japanese  towns  is 
never  artificially  turned  into  guano  or  poudrette,  but  is  sent  every 
night  and  morning  in  its  natural  form  into  the  country  around,  to 
return  again  after  a  time  in  the  shape  of  beans  or  turnips.  Thousands 
of  boats  may  be  seen  early  each  morning  laden  with  high  heaps  of 
buckets  full  of  the  precious  stuff,  which  they  carry  from  the  canals 
in  the  cities  to  the  country.  These  boats  come  and  go  with  the 
regularity  of  the  post ;  it  must  be  admitted,  however,  that  it  is  a 
species  of  martyrdom  to  be  the  conductor  of  a  mailboat  of  this 


JAPANESE  *  HUSBANDRY.  369' 

kind.  In  the  evening  long  strings  of  coolies  are  met  with  on  the 
road,  who  having  in  the  morning  carried  the  produce  of  the  coun- 
try to  the  town,  are  returning  home  each  with  two  buckets  of  ma- 
nure, not  in  a  solid  or  concentrated  form,  but  fresh  from  the  privies. 
Caravans  of  packhorses,  which  often  have  brought  manufactured 
articles  (silk,  oil,  lacquered  goods,  &c.),  a  distance  of  200  to  300 
miles  from  the  interior  to  the  capital,  are  sent  home  again  freighted 
with  baskets  or  buckets  of  manure  ;  in  such  cases,  however,  care, 
is  taken  to  select  solid  excrements. 

Thus  in  Japanese  agriculture  we  have  before  us  the  represen- 
tation of  a  perfect  circulation  of  the  forces  of  nature  :  no  link  in 
the  chain  is  ever  lost,  one  is  always  interlaced  with  the  other. 

I  cannot  refrain  here  from  drawing  a  parallel  in  this  respect 
between  the  Japanese  and  our  system.  In  our  large  farms  we  sell 
a  portion  of  the  productive  power  of  our  soil  in  the  form  of  corn, 
turnips,  or  potatoes ;  but  our  carts  which  convey  the  products  to 
the  town  or  to  the  gates  of  the  factory,  bring  back  no  compensa- 
tion. One  of  the  links  of  the  chain  is  lost.  There  is  another  por- 
tion of  our  produce  devoted  to  the  feeding  of  large  herds  of  cattle, 
of  which  a  considerable  amount  is  sent  forth  in  the  form  of  fat 
cattle,  milk,  butter,  or  wool ;  this  again  is  never  returned,  and 
thus  a  second  link  of  the  chain  is  lost.  Another  small  portion  we 
and  our  labourers  consume.  This  last  portion  at  least  might  be 
turned  to  proper  account,  if  we  only  knew,  like  the  Japanese,  to 
save  and  use  it  more  carefully  and  wisely.  Will  any  one  venture 
to  assert  that  the  privy  manure  of  our  farms  is  of  the  least  real 
importance  ?  I  verily  believe  that,  under  present  circumstances, 
the  privy  manure  of  an  estate  of  a  thousand  acres  would  be  barely 
sufficient  for  half  an  acre  of  ground.  There  remains,  then,  from 
our  present  agricultural  system,  out  of  the  entire  productive  power 
withdrawn  by  the  crops  from  the  soil,  only  that  portion  returned 
by  our  cattle,  a  small  part  indeed  of  the  whole,  if  we  take  into 
consideration  its  bulk,  and  reflect  in  how  concentrated  a  form  we 
have  disposed  of  the  rest  of  that  power  in  the  shape  of  grain,  milk, 
or  wool. 

It  may  be  objected,  I  am  quite  aware,  that  it  is  strange  that 
our  system  of  keeping  large  stocks  of  cattle  does  succeed  in  lead- 
ing to  a  high  state  of  cultivation  and  abundant  produce.  I  admit 
the  fact,  only  let  us  ascertain  first  its  true  significance.  It  is,  above 
all,  necessary  to  settle  about  the  true  acceptation  of  the  term  '  cul- 
ture.' If  by  '  culture  '  is.meant  the  capability  of  the  soil  to  give 
permanently  high  produce,  by  way  of  real  interest  on  the  capital 
of  the  soil,  I  must  altogether  deny  that  our  farms  (with  perhaps  a 
few  exceptions),  can  properly  be  said  to  be  in  a  satisfactory  state 
of  culture.  But  we  have  by  excellent  tillage  and  a  peculiar  meth- 
od of  manuring,  put  them  in  a  condition  to  make  the  entire  pro- 
ductive power  of  the  soil  available,  and  thus  to  give  immediately 
full  crops.  It  is  not,  however,  the  interest  that  we  obtain  in  such 

16* 


370  APPENDIX   G. 

crops,  but  the  capital  itself  of  the  soil  upon  which  we  are  drawing. 
The  more  largely  our  system  enables  us  to  draw  upon  this  capital, 
the  sooner  it  will  come  to  an  end.  The  term  '  culture '  applied  to 
such  a  proceeding  is  a  misnomer.  The  peculiar  method  of  ma- 
nuring alluded  to  consists  merely  in  our  endeavouring  to  feed  the 
soil  of  our  fields  with  the  largest  possible  supply  of  azotised  mat- 
ter. Now,  ammonia  and  the  other  azotised  compounds  may  no 
doubt  be  looked  upon  as  excellent  agents  to  stir  up  the  hidden  and 
slumbering  forces  of  the  soil.  But  after  all,  these  agents  may  be 
regarded  somewhat  in  the  light  of  a  banker,  who  kindly  exchanges 
the  pound  we  have  to  spend  for  thirteen  shillings ;  and  then  we 
can  spend  the  change  fast  enough.  This  accounts  for  the  large 
party  amongst  us  who  love  and  cherish  the  obliging  banker. 

This  is  the  great  difference  between  European  and  Japanese 
culture.  The  former  is  simply  a  delusion,  which  will  be  detected 
sooner  or  later.  Japanese  cultivation,  on  the  other  hand,  is  actual 
and  genuine ;  the  produce  of  the  land  represents  indeed  the  inter- 
est of  the  capital  of  the  soil's  productive  power.  As  the  Japanese 
knows  that  he  has  to  live  upon  that  interest,  his  first  care  is  de- 
voted to  keeping  the  capital  intact.  He  only  takes  away  from  his 
soil  with  one  hand,  if  he  can  make  up  the  loss  with  the  other ; 
and  he  never  takes  more  than  he  can  return.  He  never  endeavours 
to  force  the  production  by  large  supplies  of  azotised  matters. 

The  fields  in  Japan  do  not,  therefore,  as  a  general  rule,  present 
that  luxuriant  aspect  which  gratifies  our  sight  occasionally  at 
home.  There  are  no  impenetrable  forests  of  straw  from  six  to 
eight  feet  high,  to  be  seen,  nor  turnips  weighing  100  Ibs.,  with 
99  Ibs.  of  water  in  them.  There  is  nothing  extravagant  in  the 
sight  of  Japanese  crops.  But  what  distinguishes  them  most  favour- 
ably as  compared  to  ours  is  their  certainty  and  uniformity  for  thou- 
sands of  years.  The  real  produce  of  land  can  be  calculated  only  by 
the  average  crops  of  a  long  number  of  years. 

If  additional  proof  were  needed  to  show  that  the  state  of  culti- 
vation is  very  superior,  and  that  the  land  yields  abundant  produce, 
I  would  point  to  the  fact  that  the  Japanese  empire,  which  covers 
an  area  similar  to  Great  Britain  and  Ireland,  and  of  which  one- 
half  at  the  most,  from  the  hilly  nature  of  the  country,  can  be  looked 
upon  as  fit  for  tillage,  not  only  contains  a  larger  number  of  inhab- 
itants than  Great  Britain  and  Ireland,  but  maintains  them  without 
any  supply  of  food  from  other  parts.  Whilst  Great  Britain  is 
compelled  to  import  corn  from  other  countries,  to  the  extent  of 
many  millions  per  annum,  Japan  since  the  opening  of  its  ports 
actually  exports  no  inconsiderable  quantities  of  food. 

SECTION  II. 

TILLAGE    OF   THE   SOIL. 

Deep  cultivation  of  the  soil  has  become  a  kind  of  proverb  with 
our  modern  writers  on  agriculture  ;  and  the  principle  of  the  sys- 


JAPANESE   HUSBANDRY.  371 

tern  is,  at  least,  fully  admitted  on  all  hands,  the  only  objection  oc- 
casionally raised  against  it  being  that  it  requires  a  large  supply  of 
manure.  But  the  most  enthusiastic  admirer  of  the  system  in 
Europe  can  hardly  conceive  how  universally  and  in  what  high  per- 
fection it  is  carried  on  in  Japan. 

The  Japanese  husbandman  has  come  to  treat  his  field  as  a 
plastic  material,  to  be  turned  to  account  in  any  way  or  form  he 
pleases,  just  as  a  tailor  may  cut  out  of  a  piece  of  cloth,  cloaks, 
coats,  trowsers  or  vests,  and  occasionally  makes  the  one  out  of  the 
other.  To-day  we  find  a  plot  of  ground  covered  with  a  wheat 
crop ;  in  eight  days  the  wheat  is  reaped,  and  one  half  of  the  field 
is  transformed  into  a  swamp  thoroughly  saturated  with  water,  in 
which  the  farmer,  sinking  up  to  his  knees,  is  busy  planting  rice, 
whilst  the  other  half  is  a  broad  and  dry  plot,  raised  2  or  2|  feet 
above  the  rice  swamp,  and  ready  to  receive  cotton,  or  sweet  pota- 
toes, or  buckwheat.  It  often  happens  also  that  a  square  plot  in 
the  centre  is  turned  into  a  dry  bed,  surrounded  by  a  broad  rice 
swamp ;  and  as  the  water  must  cover  the  surface  of  the  latter 
only  slightly,  the  levelling  must  have  been  effected  with  great 
care,  and  with  the  use  of  instruments. 

The  whole  of  this  work  has  been  done  by  tbe  farmer  and  his 
small  family  in  a  very  short  time.  That  it  could  be  accomplished 
in  so  short  a  time  is  a  proof  of  the  great  depth  of  the  loose  araUe 
soil,  even  after  a  harvest ;  and  that  the  farmer  could  venture  to  do 
so  without  troubling  himself  about  the  next  crop,  is  a  sign  of  the 
abounding  wealth  of  the  soil  in  mineral  constituents.  It  is  only 
when  great  depth  of  the  loose  arable  soil  is  combined  with  a  plen- 
tiful store  of  mineral  constituents  that  deep  tillage  of  the  ground 
can  truly  be  resorted  to.  The  description  here  given  is  not  a  mere 
fiction  or  creation  of  the  imagination,  but  a  faithful  statement  of 
facts  such  as  I  have  had  occasion  to  -witness  by  the  hundred. 
Considering  that  rice  requires  at  least  from  1  to  1-J  feet  of  cultivated 
soil,  and  adding  to  this  half  the  height  of  the  raised  bed,  viz.  1  to  1| 
feet,  this  gives  a  cultivated  depth  of  arable  soil  of  from  2  to  3  feet. 

This  system  of  working  the  land  at  pleasure  either  as  a  raised 
dry  plot  or  as  a  swamp,  is  indeed,  at  present,  in  Japan,  simply  a 
proof  of  the  existence  of  deep  tillage ;  but  it  is  clearly  evident  that 
it  must  have  been,  at  one  time,  also,  the  means  of  effecting  it.  If 
we  are  always  to  wait  until  we  have  collected  a  sufficient  excess 
of  manure  (at  the  best  but  a  very  relative  term),  before  proceeding 
to  deepen  the  arable  crust  of  our  land,  we  may  certainly  predict 
that  the  system  will  but  very  rarely  make  any  progress  with  us. 
Everybody  knows  that  one  cannot  learn  to  swim  without  going 
into  the  water. 

The  introduction  and  constant  progress  of  the  system  of  deep 
tillage  have  been  powerfully  assisted  in  Japan  by  the  practice  pur- 
sued from  time  immemorial  of  growing  all  crops  in  drills.  With 
the  advantage  of  this  method  we  have  also  long  been  familiar. 


372  APPENDIX  G. 

Among  the  favourable  features  presented  by  the  cultivation  of  root 
crops,  our  books  of  agriculture  always  place  in  a  prominent  rank 
the  fact  that  it  enables  the  farmer  to  deepen  the  arable  soil  of  his 
land.  All  our  gardeners,  at  least,  have  long  ago  adopted  it. 

I  was  not  fully  aware  of  the  true  importance  of  the  method  of 
growing  crops  in  drills,  until  I  had  occasion  to  see  it  carried  out 
to  the  fullest  extent  in  Japan.  We,  in  Europe,  are  as  yet  far  from 
having  adopted  this  plan  as  an  essential  part  of  our  system  of  hus- 
bandry; we  look  upon  the  question  still  in  a  very  one-sided  point 
of  view,  only  in  reference  to  the  individual  crop  which  we  wish  to 
grow.  But  the  Japanese  farmer  has  raised  it  to  the  rank  of  a  sys- 
tem, by  which  he  has  fully  emancipated  himself  from  the  neces- 
sity of  paying,  as  we  are  compelled  to  do,  the  least  regard  to  the 
rotation  of  crops.  By  its  means  he  has  truly  become  master  of  his 
land.  He  has  not  only  succeeded  in  growing  crops  at  the  same 
time  which  used  to  follow  each  other,  but  he  has  carried  to  the 
highest  perfection  the  principle  of  mixed  cultivation,  which  begins 
now  to  find  favour  also  with  our  European  farmers  :  he  has,  in  this 
respect  put  an  end  to  our  confused  and  haphazard  way  of  mixing 
crops  on  the  same  field,  having  by  the  adoption  of  the  method  of 
drill  planting,  brought  order  and  regularity  into  the  system.  The 
following  description  of  the  Japanese  system  may  serve  by  way 
of  illustration. 

We  have  a  Japanese  field  before  us,  in  the  middle  of  October, 
with  nothing  but  buckwheat  upon  it.  The  buckwheat  is  planted 
in  rows,  24  to  26  inches  apart ;  the  intervening,  now  vacant,  space 
had  been  sown  in  spring  with  small  white  turnip-radishes,  which 
have  already  been  gathered.  These  intervening  vacant  spaces  are 
now  tilled  with  the  hoe  to  the  greatest  depth  attainable  by  the  im- 
plement. A  portion  of  the  fresh  earth  is  raked  from  the  middle 
up  to  the  buckwheat,  which  is  now  in  full  flower :  a  furrow  is  thus 
formed  in  the  middle,  in  which  rape  is  sown,  or  the  grey  winter 
pea,  the  seed  being  manured  in  the  manner  already  described,  and 
seed  and  manure  afterwards  covered  with  a  layer  of  earth.  By  the 
time  the  rape  or  the  peas  have  grown  one  to  two  inches  high,  the 
buckwheat  is  ripe  for  cutting.  A  few  days  after  the  rows  in 
which  it  stood  are  dug  up,  cleared,  and  sown  with  wheat  or  win- 
ter turnips.  Thus  crop  follows  crop  the  whole  year  through.  The 
nature  of  the  preceding  crop  is  a  matter  of  indifference,  the  selec- 
tion of  the  succeeding  one  being  determined  by  the  store  of  ma- 
nure, the  season,  and  the  requirements  of  the  farm.  If  there  is  a 
deficiency  of  manure,  the  intervening  rows  are  allowed  to  lie  fal- 
low, until  a  sufficient  quantity  has  been  collected  for  them. 

This  system,  as  a  whole,  has  also  this  great  advantage,  that 
the  manure  may  be  used  at  all  times,  and  need  never  lie  idle  as  a 
dead  capital  bearing  no  interest ;  and  moreover,  perhaps,  the  most 
important  point  of  all  is,  that  a  direct  ratio  is  thereby  secured  be- 
tween the  power  of  the  soil,  as  shown  in  the  crops,  and  the  stock 


JAPANESE  HUSBANDRY.  373 

of  manure  on  hand,  a  ratio  not  disturbed  here  by  artificial  means 
or  by  any  '  tour  de  force?  Expressed  in  other  words,  the  in- 
come and  expenditure  of  the  soil  are  always  kept  evenly  bal- 
anced. 

I  have  seen  this  system  carried  out  to  the  fullest  attainable 
degree  in  the  vicinity  of  large  towns,  such  as  Jeddo,  also  in  par- 
ticularly fertile  valleys,  and  on  fields  bordering  on  the  great  high- 
ways. Here  crop  succeeded  crop,  manure  followed  manure. 
Here  the  plot  of  ground  produced  much  more  than  could  be  con- 
sumed on  it ;  but  the  great  city  and  the  privies  on  the  high  road 
returned  a  supply  of  manure  to  balance  the  export  of  produce. 

I  have,  however,  also  had  occasion  to  visit  farms  situated  on 
some  hilly  part  far  away  from  the  high  road,  and  only  recently 
reclaimed  and  cultivated.  As  the  Japanese  farmer,  as  a  general 
rule,  prefers  the  valleys  to  the  hilly  ground,  the  supply  of  manure 
here  is  more  restricted  and  more  difficult,  and  any  addition  to  it 
from  towns  or  by  travellers  is  almost  altogether  out  of  the  ques- 
tion. Here  I  found  occasionally  only  one  crop  on  the  ground ; 
yet  the  rows  were  so  wide  asunder  that  another  crop  would  have 
found  ample  space  between  them.  With  this  system  it  is  at  least 
possible  to  till  properly  and  repeatedly  the  intervening  spaces, 
which  are  intended  to  receive  the  next  crop ;  besides  the  constant 
supply  of  fresh  earth  to  the  present  crop,  by  raking,  places  a 
larger  store  of  soil  at  the  disposal  of  the  latter  than  could  be  done 
in  any  other  way.  In  this  manner  only  the  one-half  of  the  field 
(corresponding  to  the  limited  supply  of  manure)  is  actually  made 
to  produce ;  but  the  system  of  planting  the  crop  in  drills  wide 
asunder  always  gives  a  much  more  abundant  return  than  could 
possibly  be  obtained,  if  the  one-half  of  the  field  as  a  continuous 
plot  were  completely  sown,  the  other  half  being  allowed  to  lie 
fallow.  As  the  home  production  of  manure  or  the  importation  of 
it  from  other  parts,  increases,  the  farmer  proceeds  to  fill  part  also 
of  the  vacant  rows,  which  thus  leaves  only  the  third  or  fourth 
part  of  the  field  fallow,  until,  at  last,  every  row  is  made  to  produce 
crops. 

How  wide  the  difference  between  this  system  and  ours! 
When  we  break  up  and  till  a  plot  of  ground,  we  begin  by  extract- 
ing from  it  three  or  four  harvests,  without  bestowing  a  particle  of 
manure,  and  apply  manure  only  when  the  soil  is  exhausted. 
The  Japanese  husbandman  never  breaks  up  a  plot  of  land,  unless  he 
possesses  a  small  stock  of  manure,  which  he  may  invest  in  the 
ground ;  and  even  then  he  only  cultivates  this  new  plot  to  the  ex- 
tent his  supply  of  manure  will  permit.  This  rational  proceeding 
shows  the  deepest  insight  into  the  nature  of  the  system  of  agri- 
culture to  be  pursued  with  a  reasonable  prospect  of  securing  a 
constant  succession  of  remunerative  crops.  No  other  illustration 
can  so  clearly  show  the  difference  between  our  European  way  of 
viewing  the  matter  and  the  Japanese.  We,  in  Europe,  cut  down 


374:  APPENDIX   H. 

the  trees  on  a  forest  plot,  sell  the  timber,  grub  up,  plough  and  till 
the  ground,  and  then  proceed  to  dispose  of  the  productive  power 
of  the  new  soil,  in  three  cereal  crops,  obtained  without  the  least 
supply  of  manure ;  or  we  may  possibly  assist  in  accelerating  the 
exhaustion  of  the  ground  by  a  small  dose  of  guano.  All  that  this 
course  of  proceeding  is  calculated  to  accomplish  is,  that  we  have 
now  to  distribute  the  manure  hitherto  produced  on  our  estate  over 
a  somewhat  more  extended  surface  than  formerly.  When  the  Jap- 
anese husbandman  breaks  up  a  plot  of  ground,  he  finds  a  virgin 
soil,  the  productive  power  of  which  he  has  not  the  least  intention 
of  impairing.  He  therefore,  from  the  very  outset,  takes  care  to 
establish  a  proper  balance  between  crop  and  manure,  expenditure 
and  income,  maintaining  thus  intact  the  productive  power  of  the 
ground,  which  is  all  that  can  reasonably  be  attempted  by  any  ra- 
tional husbandman  ('  Annul,  der  Preuss.  Landwirthschaft,'  Janu- 
ary, 1862). 


APPENDIX  H  (page  237). 

"We  would  earnestly  recommend  all  inquiring  travellers  in 
other  parts  of  the  world,  to  endeavour  to  ascertain,  above  all 
things,  what  are  the  proportions  of  the  annual  produce  of  the 
various  cereals  and  cultivated  plants  raised  in  a  continued  succes- 
sion of  crops  on  unmanured  soil  of  different  kinds  in  the  same 
place,  and  under  the  climatic  influences  of  widely  differing  degrees 
of  latitude.  In  so  far  as  the  author  has  been  able  to  obtain  re- 
liable information  on  the  matter,  from  various  countries,  more 
especially  from  the  torrid  zone,  a  careful  examination  of  the  facts 
ascertained  would  appear  to  refute  everywhere  the  old  wide- 
spread error  that  a  very  fruitful  soil,  under  favourable  climatic 
conditions,  in  the  tropics  for  instance,  will  continue  inexhaustible, 
even  without  receiving  back  from  the  hand  of  man  the  mineral 
matters  removed  in  the  crops.  Even  in  the  most  enchanting  lands 
of  the  tropical  zone,  on  the  most  fruitful  volcanic  earth,  such  as  is 
found  in  the  old  country  of  the  Incas,  tlie  tableland  of  Quito, 
Imbabura,  Eiobamba,  Cuenca,  &c.,  a  long-continued  succession 
of  crops  drained  the  soil  wherever  it  was  impracticable  to  convey 
to  the  fields  by  artificial  irrigation  the  mud  carried  down  by  the 
torrents  of  the  Andes.  In  those  regions  water,  aided  by  the  wide- 
spread old  volcanic  mud  streams  (Lodozales),  plays  the  part, 
which  guano  and  farm-yard  manure  do  elsewhere,  of  restoring  to 
the  soil  the  mineral  constituents  removed  by  a  continued  succes- 
sion of  crops.  In  most  of  the  provinces  of  Persia,  more  especi;  lly 
in  Aserbeidschan  and  in  a  great  portion  of  Armenia  and  Asia 
Minor,  the  irrigation  canals  everywhere  met  with  serve  the  pur- 


MINERAL   MATTERS    SUPPLIED    BY    IRRIGATION.        375 

Eose,  not  so  much  of  moistening  the  ground,  as  of  conveying  to  the 
md  in  the  valleys  the  mineral  detritus  washed  from  the  moun- 
tains at  the  time  of  the  melting  of  the  snow.  This  method  of 
artificial  manuring  by  irrigation  is  commonly  applied  also  in 
those  countries  where  there  is  no  lack  of  rain  and  dew.  It  sub- 
serves the  same  purpose  as  the  mud  of  the  Nile  in  Egypt,  viz.  to 
replace  the  action  of  farm-yard  manure.  Where  the  mineral  con- 
stituents removed  by  a  long  succession  of  crops  are  not  restored  to 
the  ground  either  by  animal  manure,  or  by  irrigation,  the  soil  is 
almost  completely  drained  of  its  productive  powers,  as  is  the  case, 
for  instance,  in  certain  parts  of  the  extensive  tablelands  of  Tacun- 
ga  and  Ambato  (in  the  South  American  State  Ecuador),  where 
barley  will  often  barely  give  a  two  or  threefold  return,  notwith- 
standing the  frequent  alternations  of  rain  and  sunshine.  From  the 
most  reliable  information  obtained  by  me,  even  the  most  fertile 
estates  in  San  Salvador  and  Ohiriqui,  in  'Central  America,  with 
their  most  fruitful,  loose,  trachytic  soil,  abounding  in  potash  and 
silica,  cannot  show  a  single  field  on  which  maize  has  been  grown 
for  thirty  years  running  without  a  considerable  reduction  of  prod- 
uce— a  fact  which  sufficiently  refutes  the  old  mistaken  notion  of 
the  inexhaustible  fertility  of  the  soil  in  the  tropics. 

On  the  western  coast  of  Peru  only  those  parts  are  extremely 
sterile,  where  no  little  artificial  canals  convey  to  the  dry  soil  the 
water  from  the  torrents  of  the  Andes,  which  carries  with  it  the 
mineral  detritus  washed  from  the  declivities  of  the  mountains. 
Wherever  such  artificial  canals  exist,  and  the  conditions  of  the 
ground  are  favourable,  the  soil  on  the  coast  as  well  as  in  the  interi- 
or of  Peru  and  Bolivia  is  almost  as  productive  as  in  the  interior  of 
the  highlands  of  Ecuador,  New  Granada,  and  Gautemala.  But  it 
is  not  the  water  which  is  the  agent  in  maintaining  the  steady  pro- 
ductiveness of  the  soil,  but,  as  in  the  case  of  the  Delta  of  the  Nile 
in  Egypt,  it  is  the  mud  carried  along  with  the  water,  and  which 
has  been  washed  away  from  the  disintegrated  rocks  of  the  Andes. 
The  constituents  of  this  mineral  detritus,  which  are  partly  con- 
tained in  the  water  in  a  state  of  minute  mechanical  division,  and 
partly  held  in  chemical  solution,  are  brought  to  the  fields  by  small 
channels.  The  water  thus  conveyed  from  the  mountains  in  innu- 
merable furrows  is  soon  absorbed  by  the  soil  or  evaporated,  leav- 
ing a  rich  fertilising  deposit  behind.  Pure  rain  water  would  be 
of  very  little  avail,  as,  for  instance,  in  the  extensive  tableland  of 
Tacungar,  with  its  barren  pumice  stone  fields,  where  quite  near 
the  equator  rain  pours  down  almost  daily  during  nine  months  of 
the  year.  It  is  not  the  atmospheric  water  that  acts  as  the  fertil- 
ising agent,  but  the  muddy  streamlets  from  the  Andes.  In  Peru 
the  fertilising  action  of  guano  is  more  enduring  than  in  England, 
because  the  potash  which  the  guano  does  not  restore  to  the  soil,  is 
there  supplied  in  the  detritus  from  the  trachytic  constituents  of  the 
Andes  ridge,  which  abound  in  felspar.  This  natural  mineral  ma- 


376 


APPENDIX   I. 


mire  is  of  the  same  high  value  in  the  South  American  lands  of  the 
Andes  chain  as  the  fertile  Loss,  accumulated  by  the  great  flood  in 
past  ages  at  the  foot  of  the  Bavarian  and  Swiss  Alps.  It  is  a  fact 
full  of  meaning  that  the  inhabitants  of  those  parts  of  America 
should  have  arrived  at  the  same  simple  means  of  restoring  to  the 
land  the  mineral  constituents  carried  away  by  the  crops,  which 
are  at  the  present  day  generally  resorted  to  also  under  similar 
favourable  conditions  of  the  ground  in  the  mountainous  regions  of 
Asia  Minor,  Armenia,  Grusia,  Western  Persia,  as  well  as  in  the 
north  of  Mesopotamia  (Mossul),  and,  if  I  mistake  not,  in  Thibet 
also.  The  waters  of  the  rivers  Kur,  Araxes,  Euphrates  and  Tigris, 
are  in  spring  just  as  turbid  and  as  much  impregnated  with  mud, 
which  simply  means  earthy  particles,  as  the  Nile,  and  as  the  East 
Persian  river  Herirud,  which  it  is  well  known  is  altogether  ab- 
sorbed up  in  fields  and  gardens.  The  experience  of  ages  past  has 
no  doubt  taught  the  inhabitants  of  these  ancient  countries,  in  both 
hemispheres,  this  way  of  restoring  to  their  fields  the  incombusti- 
ble constituents  removed  from  them  in  the  produce  carried  away 
to  the  large  towns  (Professor  Dr.  Moritz  Wagner ;  see  supplement 
to  'Augsb.  Allg.  Zeitung,'  No.  36,  February  5,  and  No.  173, 
June  22,  1862). 


APPENDIX  I  (page  321). 

ANALYSIS   OF    CLOVER    MADE   BY    DR.   PINCUS. 

100  parts  of  air-dried  clover  contained, — 


Unmanured. 

Manured  with 
sulphate  of  magnesia. 

Manured  with 
sulphate  of  lime. 

"fl 

I 

• 

C 

a 
a 

2 

•a 

03 

2 

55 

1 

0 

s 

2 

w 

1 

i/3 

1 

i 

E 

i 

i 
I 

1 

i 

i 

Water  

12-25 

13-04 

15-05 

12-95 

13-00 

14-45 

12-12 

13-27 

11-85 

10-70 

12-24 

11-60 

Vegetable  fibre  

39-55 

15-07 

16-36 

28-85 

39-47 

12-58 

17-08 

29-70 

38-75 

13-73 

16-96 

29-87 

Mineral  constituents 

5-05 

11-16 

6-32 

6-95 

6-75 

10-97 

7-47 

7-94 

6-65 

11-45 

7-45 

7-96 

Protein  substances. 

10-15 

22-08 

17-59 

14-70 

11-42 

24-37 

19-59 

15-81 

12-34 

28-74 

20-57 

17-45 

Hydrate  of  carbon  . 

33-00 

38-65 

44-68 

36-55 

29-36 

37-63 

43-74 

33-28 

30-41 

35-33 

42-78 

33-12 

100-00 

100-00 

100-00 

100-00 

100-00 

100-00 

100-00 

100-00 

100-00 

100-00 

100-00 

100-00 

Total  quantity  of  nu- 
tritive substances. 

43-15 

60-73 

62-27 

51-25 

40-78 

62-00 

63-33 

49-09 

42-75 

64-12 

63-35 

50-57 

Proportion    of    the 

protein  substance 

to  the  hydrate  of 

carbon                •• 

1:3-25 

1  :  1-75 

1  :  2-54 

1  :  2  46 

1:2-57 

1:1-54 

1:223 

1:2-10 

1:2-46 

1:1-23 

1:2-08 

1:1-90 

ANALYSIS   OF  CLOVER. 


377 


ASH  CONSTITUENTS. 
100  parts  of  ash  contained, — 


Clover 
unmanured. 

Clover  manured 
with  sulphate 
of  magnesia. 

Clover  manured 
with  sulphate 
of  lime. 

Chlorine              

1'93 

1"22 

1*73 

Carbonic  acid  .           .... 

21*43 

21*75 

19*17 

Sulphuric  acid  

1*33 

2'86 

3*29 

Phosphoric  acid  

7-97 

8  '49 

8*87 

Silicic  acid  

2-67 

2'55 

3*08 

Potash  

33-58 

32*91 

35*37 

Soda  

2-12 

3'03 

2*73 

21'71 

20*66 

19*17 

Magnesia  

5'87 

5*27 

5*47 

0*94 

1*22 

0*94 

99-55 

99-46 

99-82 

CALCULATED  UPON  THE  ASH  FREE  FROM  CARBONIC  ACID. 


Clover 
unmanured. 

Clover  manured 
with  sulphate 
of  magnesia. 

Clover  manured 
•with  sulphate 
of  lime. 

Chlorine  .  .  .•  

2*46 
1*69 
10*14 
3-40 
42-73 
2-70 
27-62 
7-47 
1-20 

1.56 
3*02 
10*85 
3-26 
42-05 
3-87 
26-40 
6*74 
1-56 

2-14 
4-07 
10-97 
3-81 
43*77 
3-37 
23-72 
6-77 
1*10 

Sulphuric  acid  

Phosphoric  acid  

Sil  icic  acid  

Potash  

Soda  

Lime  

Magnesia  

Sesquioxide  of  iron  

99-41 

99*31 

99-78   • 

The  remarkable  investigations  by  Dr.  Grouven  of  the  clover 
disease  deserve  also  a  place  here. 

The  so-called  '  clover  disease '  manifests  itself  in  the  clover 
plant,  at  the  period  of  flowering,  by  the  appearance  of  a  multitude 
of  brown  spots  of  cryptogamic  plants  covering  stems  and  leaves. 
The  result  of  the  affection  is  not  simply  a  failure  of  the  clover 
crop,  but  the  produce  reaped  is  unwholesome  for  cattle. 

In  his  examination  -of  the  diseased  clover,  Grouven  compared 
the  organic  and  the  ash  constituents  of  the  diseased  with  those  of 


378 


APPENDIX  I. 


the  healthy  plant.  Both  the  healthy  and  the  diseased  clover 
were  produced  from  a  mixture  of  seeds  of  red  clover,  lucerne,  and 
esparsette,  such  as  is  usually  grown  at  Salzmunde,  where  the 
experiments  were  made.  The  samples  for  examination  and 
analysis  were  taken  from  the  field  on  August  12.  The  analysis  of 
the  healthy  plant  was  confined  to  the  determination  of  the  organic 
substances  and  the  amount  of  ash. 

100  parts  of  air-dried  clover-hay  contained, — 


Diseased  clover. 

Healthy  clover. 

Water  

16-2 

16-2 

Protein  substances  

16-7 

11-7 

Fat  

3'6 

2-8 

Saccharine  matter,  calculated  as  starch*  
Non-azotised  compounds  unknown  

7-0 

17'9 

18-5 
11  '3 

Woody  fibre    

31-7 

si-it 

Ash  

6-9 

8'1 

100-0 

100-0 

The  composition  of  the  ash  of  the  diseased  clover  was  com- 
pared with  that  of  the  ash  of  red  clover  (Wolff)  and  esparsette 
(Way).J  The  ashes  were  calculated  after  deduction  of  carbonic 
acid,  sand,  clay,  and  sesquioxide  of  iron. 


Diseased  clover. 
(GROUVEN.) 

lied  clover. 
(  WOLFF.) 

Esparsette. 

(WAT.) 

Potash  .. 

3'32 

35-5 

35-8 

Soda  

0'87 

0'7 

3*5 

55-71 

32-8 

35'9 

Magnesia                   .     .  . 

13*08 

8  "4 

5'5 

Chlorine              .         . 

2-76 

3'5 

2'0 

Sulphuric  acid  .         ... 

13  '46 

3'3 

2*8 

Phosphoric  acid  ...       . 

5'99 

8  '4 

9'6 

Silicic  acid  

4'88 

7-0 

4*3 

200-07 

99-6 

99-4 

Grouven  is  led  to  conclude  from  the  result  of  his  examination 
that  the  primary  cause  of  the  clover  disease  is  attributable  to  a 


*  Substances  convertible  into  sugar  by  sulphuric  acid. 
t  With  O'l  of  ash  and  0'184  of  protein  substances. 
\  Compare  also  the  preceding  analysis  by  Dr.  Pincus. 


CLOVER  DISEASE.  379 

change  in  the  chemical  composition  of  the  plant,  which  again  is 
caused  by  an  altered  condition  of  the  soil.  The  very  considerable 
deficiency  of  phosphoric  acid  and  potash  in  the  ash  of  the  diseased 
plant  is  certainly  remarkable  (' Zeitschrift  der  landwirthschaft- 
lichen  Central vereins  der  Provinz  Sachsen,1861,'  page  73). 


INDEX. 


Absorption,  power  of,  in  Boils,  for  food 
of  plants,  75 

in  charcoal,  for  colouring  matter 

and  gases  is  a  surface  attraction,  76 

in  soils,  is  accompanied  by  chem- 
ical decomposition,  79 

for  compounds  of  soda,  and  for 

silicic  acid,  88,  137 

varies  in  each  soil,  137 

for  potash,  136 

for  silicic  acid  and  ammonia,  138 

is  inversely  as  the  diffusibility 

of  food, 137 

shows  the  depth  to  which  food 

penetrates,  215 

— in  turf,  112 

—  by  roots  of  plants  not  osmotic,  63 
: value  of  knowledge  of  to 

agriculturists,  217 

—  of  nutriment  by  roots  of  plants,  94 

—  of  silicic  acid,  influence  of  organic 
matter  on  the,  89 

—  number  of  soils,  meaning  of,  139 
for  ammonia,  potash,  phos- 
phate of  lime,  and  phosphate  of  mag- 
nesia and  ammonia,  139 

importance  of,  to  agricultu- 
rists, 141 

Agriculture,  progress  of,  impossible  if 
dependent  on  a  supply  of  ammonia, 
304 

—  in  Europe  still  young,  233 
Agricultural  produce,  the  permanence 

of,  regulated  by  a  law  of  nature,  232 
Agrostemma  cithago,  ash  of,  226 
Ahrend's  examination  of  the  oat  plant  at 

different  stages  of  growth,  49 
Aloe,  food  of,  stored  in  leaves,  41 
Alumina  in  club  moss,  71 
Ammonia,  absorbed  by  different  soils,  138 

—  absorption,  number  of,  138 

—  absorbed  strongly  in  soils,  rich    in 
humus,  143 

—  action   of  the   salts    of,   by   them- 
selves and  in  guano,  247,  281,  287 

—  action  of  salts  of,  on    earthy  phos- 
phates, silicates,  &c.,  88 


Ammonia,  amount  of  in  rain  and  dew,  274 

—  always  present  in  air,  275 

—  calculation  of  amount  of,  that  would 
be  required  in  Europe,  305 

—  compounds  of,  by  themselves  not  im- 
portant, 301 

—  cost  of,  precludes  its  extensive  use, 
305 

—  comportment  of,  with  arable  soil,  137 

—  diffusibility  in  soils,  88 

—  in  drain  water,  98 

—  in  lysimeter  waters,  99 

—  in  spring  and  river  water,  103 

—  salts  of,~as  food  and  as  means  of  dis- 
tributing food  in  soils,  134, 138 

—  in  farm-yard   manure  and  soils  not 
separable  by  distillation  with  alkalies, 
295,  298 

—  In  manures  compared  with  corn  pro- 
duced, according  to  Lawes,  304 

—  manufactured  too  limited  in  quantity 
to  be  trusted  to,  305 

—  use  of,  limited  by  its  price,  307 

—  nitrite  of,  formed  by  oxidation,  307 

—  loss  of,  in  lime  soils,  by  oxidation,  311 

—  theory,  281,  292 

Ammoniacal    compounds,    experiments 
with,  by  Schattenmann,  282 

by  Lawes  and  Gilbert,  283 

by  Kuhlmann,  288,  317 

and  with  guano  by  the    Ba- 
varian Agricultural  Society,  285,  817 
Anderson  on  the  growth  of  turnips,  84 
Annual  plant,  growth  of,  29,  43,  46 
Anthemis  arvensis,  ash,  analysis  of,  226 
Appendix  A,  analysis  of  birch  leaves, 
332 

—  B,  on    the    starch  in   the    stems    of 
palms,  335 

—  C,  Hale' s  vegetable  statics,  336 

—  D,  analysis  of  drainage,  lysimeter, 
river,  and  marsh  waters,  341 

—  E,  growth  of  plants  in  solutions  of 
their  food,  260 

—  F,  on  the  growth  of  beans  in  powdered 
turf,  360 

—  G,  on  Japanese  husbandry,  361 

—  H,  on  mineral  matters  supplied  by 
irrigation,  374 


382 


INDEX. 


Appendix  I,  analysis  of  clover,  878 
Aquatic  plants  from  Ohe  and  Iser,  analy- 
sis of  ash  of,  347 

Arable  soil,  absorptive  power  of,  77,  79. 
136 

abounds  in  nitrogen,  290,  294 

chemical  decomposition  produced 

by,  79 

formation  of,  78 

food  present  in,  in  state  of  physical 

combination,  81 

food  present  in,  in  state  of  chemi- 
cal combination,  82,  83 
mode  of  estimating  nutritive  mat- 
ter in,  by  chemical  analysis,  123 
Ash  constituents,  number  necessary  for 

the  growth  of  plants,  19 
necessary  for  the  formation  of  or- 
ganic compounds,  39 
Asparagus,  analysis  of  the  ash  of,  335 
Average  crop,  meaning  of,  241 

of  wheat,  rye,  and  oats,  165 

diminution  of,  in  Hessian  Rhine, 

242 


Baden,  Grand  Duchy  of,  food  of  soldiers 

in,  260 

Baker  and  Jarvis  islands,  guano,  264 
Barley,  action  of  soda  in  the  production 

of  seed  in,  319 

—  plant,  mode  of  growth  of,  155 
Bavarian  experiments  with  salts  of  am- 
monia and  guano,  285 

with  sea  salt,  317 

with  nitrates,  319 

with  superphosphates,  148 

Beans,  growth  of,  in  powdered  turf,  114, 
360  " 

Beech  leaves,  analysis  of,  332 

Black  soil,  of  Russia,  its  fertility,  214 

Biennial  plants,  growth  of,  33 

Bineau,  amount  of  nitric  acid  and  ammo- 
nia in  rain  water,  estimated  by,  274 

Bogenhausen,  experiments  with  sea  salt, 
317 

with  salts  of  ammonia  and  with 

guano, 286 

—  soil,  amount  of  nitrogen  in,  287 
Bones  acted  on  by  steam,  263 
Bone-earth,  distribution  of  in  the  soil 

effected  by  organic  matter,  86 
and  guano  compared  as  to  rapidity 

and  duration  of  action,  264 

Saxon  experiments  with,  265 

with  salts  of  ammonia,  effects  of 

compared  with  guano,  24T 
Bottgcr,  formation  of  nitrite  of  ammonia 

by,  309 
Boussingault,  amount  of  ammonia  in  air, 

275 
and  nitric  acid  in  rain  water 

and  dew,  275 
— formed  in  combustion 

of  coal  gas,  309 

—  on  the  growth  of  plants  without  ni- 
trogenous food,  56 


Centaurea,  Cyanus,  ash  of,  226 

Cereals,  meaning  of  average  crop  of,  241 

—  average  crops  of  in  Bavaria,  205 
in  Hessian  Rhine,  242 

—  conditions  for  their  growth,  144 

—  change  produced  in  the  arable  soil  by 
the  cultivation  of,  218 

—  cause  of  difference  in  corn  and  straw 
in,  193 

—  effect  of  removing  leaves,  &c.,  from, 
before  flowering,  43 

—  nitrogenous  compounds  in,  not  always 
the  same,  246 

—  influence  of  lime  or  magnesia  on  the 
nitrogenous  compounds  in,  247 

—  influence    of    temperature    on    the 
growth  of,  48 

—  ratio  between  albuminous  and  non- 
albuminous  constituents  in  seeds  of,  54 

—  increase  at  first  in  roots,  48 

—  produce  of  stalks  and  shoots  in  pro- 
portion to  the  deyelopement  of  roots,  48 

—  produce   of,   with    superphosphates, 
148, 151 

compounds  of  ammonia,  281, 

286,  287,  288 
common  salt  and  nitrate  of 

soda,  317 

Charlemagne,  records  of,  233 
Chemical  analysis  of  soils,  limited  value 

of,  214 
Clover,  analysis  of,  376 

—  ash,  analysis  of,  377 

—  diseased,  analysis  of,  377 
ash,  analysis  of,  377 

—  effect  of  gypsum  on,  321 

—  crops  bear  no  proportion  to  the  sul- 
phuric acid  in  the  experiments  of  Dr. 
Pincus,  324 

—  requires  nearly  the  same  constituents 
as  the  potato,  201 

—  and  turnips,  effect  of  in  opening  the 
soil,  97 

explanation  of  by  Lawes  and 

Gilbert,  162 

Compensation,  law  of,  232 
Compost,  146 

Compound  manures,  action  of,  not  de- 
pendent upon  one  constituent  alone, 

251 

Copper  in  ash  of  plants,  69 
Corn,  conditions  for  formation  of,  194 
Corn  and  straw,  constituents   in  soils, 

195 
relative  proportions  of  in  cereals 

affected  by  the  weather,  188 
in  the  Saxon  experiments, 

193,  198 
Crops   reaped  afford  no  indication    of 

quantity  of  nutritive  matter  in   the 

ground,  189 
Cunnersdorf,  manure  experiments,  186 

—  produce  of  unmanured  fields  of,  186 

—  nearness  of  food  in  soil  of,  192, 199 

—  produce  with  farm-yard  manure,  202 

—  increased  produce  by  farm-yard  ma- 
nure, 203 


INDEX. 


383 


Cunnersdorf,  soil,  depth  to  -which  ma- 
nure penetrates,  217 

—  produce  with  guano  compared  with 
farm-yard  manure,  255 

—  produce  with  bone-earth    and  com- 
parison with  guano,  264 

—  produce  with  rape  cake,  268 

—  experiments,  effect  of  the  nitrogen  in, 
270 


Decreasing  crops,  progress  of,  168 
Diffusion,  law  of,  does  not  explain  the 

absorption  of  food  by  roots  of  plants, 

65 

—  experiments,  68 

Disinfection  of  excrements  does  not  af- 
fect their  energy, 261 

Distribution  of  food  by  chemical  and 
mechanical  means,  95 

Drainage,  effect  of,  98,  102 

—  removal  of  siliceous  plants  by,  90 

—  water,  its  composition,  98 
analysis  of,  341 

docs  not  dissolve  the  food  of  plants, 

102,  103, 108 
Duckweed,  power  of  selection  in  roots 

of,  64 
Dung,  mechanical  action  of,  147 


Earthy  phosphates,  262 

effect  of,  less  marked  in  firet  year, 

264 
diffusion  of,  through  the  coil,  how 

effected,  84,  86, 139 
require  the  presence  of  potash  and 

silicic  acid  in  the  soil,  264 
and  guano,  comparative    experi- 
ments with,  264 
European  husbandry,  present  state  of, 

228 
decline  of,  produced  by  the  system 

of  farm-yard  manuring,  260 
illustrated  by  Hessian  Rhine 

district,  242 
Excrement,  contain  ash  of  food,  181 

—  of  man,  260 

collection  of,  in  Rastadt,  260 

—  •—  —  value  of,  260 

not  injured  by  disinfecting  with 

sulphate  of  iron,  261 
Exhaustion  of  soils,  its  nature,  83,  85,  206 

known  by  the  average  crop,  241 

in   chemical   and    agricultural 

sense,  165 

law  of,  165 

—  retarded  by  growth  of  fodder 

plants,  173 

—  of  wheat,  oat,  and  rye  soils,  170,  175 


Fallow,  83 

False  teachers  in  agriculture,  230,  237 

Farm-yard  manure,  145 


Farm-yard  manure,  effect  of,  varies  with 
the  composition  of  the  soil,  206 

—  —  depends  on  the  minimum 

nutritive  matters  in  the  soil,  207 

its  mechanical  action,  208 

restores  fertility  only  by  sup- 
plying one  or  more  deficient  ingre- 
dients of  the  soil,  207,  221 

law  regulating  the  quantity  to 

be  applied,  211 

produce  from,  203 

in  the  Saxon  experiments 

not  always  equal  to  the  quantity  ap- 
plied, 203 

why  generally  useful,  208 

Saxon  experiments  with,  203, 

211 

manuring  system,  184,  218,  227 

changes  produced  in  the  com- 
position of  the  soil  by,  218 

final  result  of,  223 

illustrated  in  the 

Saxon  experiments,  223 

Fodder  plants,  proportion  retained  in 
bodies  of  animals,  219 

—•—  transfer  food  from  subsoil  to  sur- 
face soil,  41 

Fontinalis,  antipyretica,  ash  analysis  of, 
347 

Food,  physically  and  chemically  co"m- 
bined  in  soils,  81 

—  not  absorbed  by  plants  from  solutions 
in  soils,  93,  102,  108 

—  diffusion  of,  in  soils,  how  effected, 
84,87 

by  chemical   and   mechanical 

means,  95 

—  closeness  of  in  soils,  192 


Grouven,  analysis  of  diseased  clover,  378 
Guano,  amount  of,  equivalent  to  farm- 
yard manure,  285 

—  and  bone-earth,  effects  of,  compared, 
264 

—  and  farm-y#rd  manure,  amount  of 
phosphates  and  nitrogen  in,  252 

—  from  Baker  and  Jarvis  islands,  263 

—  fertilising  action  of,  attributed  to  its 
nitrogen  or  ammonia.  247,  281 

due  in  many  cases  to  fixed 

constituents,  247 

—  deficient  in  potash,  249 

—  and    farm-yard   manure,   effects   of, 
compared,  249 

—  when  its  application  will  be  success- 
ful, 251 

—  continued  use  of,  exhausts  the  soil  of 
silica  and  potash,  252 

—  mixed  with  sulphuric  acid  and  turf 
or  sawdust,  253 

—  peculiar  effects  of,  illustrated  in  the 
Saxon  experiments  with  different  crops, 

—  and  salts  of  ammonia,  comparative 
experiments  with,  in  Bavaria,  285 

Gypsum,  316 


384: 


INDEX. 


Gypsum,  experiments  on  clover,  320 
—  action  of  ar 


325 


arable  soil  on  BO!U  lions  of, 


—  effects  the  distribution  of  potash,  and 
magnesia  in  soils,  327 


Horse-chestnut,  analysis  of  ash  of  leaves 
of,  335 

Human  excrements,  value  of,  as  manure, 
illustrated  at  Rastadt,  259 

price  of,  259 

not  injured  by  deodorising  by  sul- 
phate of  iron,  261 


Ignorant  practical  men,  239 

Iodine,  different  amount  in  different 
plants,  69 

Iron  necessary  for  plants,  68 

Irrigation,  mineral  matters  supplied  in, 
374 

—  water,  suspended  mud  of,  most  valu- 
able, 375 


Japanese  husbandry,  362 

dispenses  with  cattle  feeding,  364 

—  soil,  361 

—  supply  of  manure,  365 

—  mode  of  constructing  privies,  365 

—  mode  of  preparing  excrements  and 
compost  for  application  in  field,  366 

—  system  of  manuring,  only  one  of  top- 
dressing,  367 

—  system  of  planting  in  rows,  367, 372 

—  husbandry  compared  with  European, 
369 

—  tillage  of  the  soil,  370 

—  succession  of  plants  illustrated,  373 
Jerusalem  artichokes,  effect  of  the  cul- 
tivation of,  on  arable  soil,  215 


Knop;  experiments   of,   on  growth  of 

plants  in  solutions  of  their  food,  350 
Kolbe,  formation  of  nitrous  acid,  309 
Kotitz,  vmmanured  field  produce  from, 

186 
Kroker,  estimation  of  nitrogen  in  soils, 

290 

—  analysis  of  drainage  water,  342 
Kuhlmann,  experiments  with  salts  of 

ammonia,  288,  317 

sea  salt,  317 

lime,  330 


Large  crops  indicate  the  available  con- 
dition of  the  mineral  food,  190 

depend  on  the  closeness*of  the  nu- 
tritive substances  in  the  soil  (figure), 
190 

Lawes  and  Gilbert  on  clover  sickness, 
157 


Lawes  and  Gilbert  on  reason  of  the  fail- 
ure  of  the  experiments  of,  159 

Leaves,  principal  conditions  for  the  for- 
mation of,  226 

—  removal  of,  from  turnips,  42 

Lime  alters  the  condition  of  the  soil,  329 

—  beneficial  effect  of,  92 

—  experiments  with,  329 

—  action  of,  on  soils,  90 

on  a  drained  marshy  soil,  92 

—  water,  effect  of  arable  soils  on,  331 
Lysimeter  waters,  99 

analysis  of,  363 

M 

Magnesia,  dispersed  in  soils  by  the  agency 
of  gypsum,  327 

—  influence  of,  on  the  formation  of  nitro- 
genous compounds  in  seeds,  247 

—  necessary  to  plants,  246 

Maize,  growth  of,  in  solutions  of  its 
food, 375 

—  in  flower,  produces  seeds  if  placed  in 
water,  52 

Manure,  nature  of,  180 

—  and  tillage,  134 

—  change  in  the  classification  of,  292 

—  beneficial  action  of,  in  restoring  the 
relative  proportions  of  mineral  matters 
in  soils,  130 

—  excessive  use  of,  gives  no  advantage, 
207 

—  reason  of  decreasing  value  of,  by  sys- 
tem of  rotation,  222 

—  nitrogen,  classification  of,  279 

—  action  of,  not  always  proportional  to 
quantity  used,  209 

Manured  land,  produce  of,  in  Saxon  ex- 
periments, 203 

Marine  plants,  power  of  selection  of  food 
in  roots  of,  64 

Matricaria  chamomilla,  ash  of,  227 

Maiisegast,  unmanured  field,  produce 
from,  186 

Mayer,  experiments  on  soils  with  caustic 
alkalies,  295 

Meadow  grass,  effect  of  sea-salt  on,  321 

Metals  found  in  plants,  67,  68 

Mineral  matters,  absorption  of,  by  soils, 
126 

to  be  restored,  vary  in  different 

soils,  239 

restored  by  farm-yard  manure,  219 

lost  in  crops  in  the  Saxon  experi- 
ments, 224 

restoration  of  all,  necessary,  239 

Minimum,  law  of,  207,  210 

Monocarpous  plants,  have  distinct  pe- 
riods of  growth,  40 

Moss  water,  analysis  of,  372 


N 


Naegeli,    experiments    on    nutrition  of 

plants,  112 
Nile,  valley  of,  reason  of  its  permanent 

fertility,  236 


INDEX. 


385 


Nitrate  of  ammonia,  formation  of,  308 

Nitrate  of  soda,  318 

action  of,  on  earthy  phosphates, 

88 
experiments  on  cereals  with,  by 

Bavarian  Society,  318 
Nitric  acid  in  rain  water,  274 
Nitrogen  classification  of  manures,  279 

—  esteemed  chief  agent  in  manures,  278 

—  indefinite  idea  of,  in  manures,  279 

—  assimilable  and  sparingly  assimilable, 
280 

—  amount  of  in  soils,  289 

—  amount  of,  in  different  layers  of  soils 
illustrated  in  Russian  black  soil  and  in 
Caen  soil,  294 

—  cause  of  the  inactivity  of  the  great 
mass  of,  in  soils,  302 

—  most  abundant  in  the  upper  ten  inches 
of  soils,  294 

—  in  soils  and  farm-yard  manure  com- 
•  pared  as  to  effect,  298 

—  profit  and  lossof,  in  the  Saxon  experi- 
ments, 276 

Nitrogen   compounds,   function   of,   in 

seeds,  58 

in  annuals,  58 

in  perennials,  60 

in  soils  bear  no  ratio  to  their  pro- 
ductive powers,  290 
supposed  different  forms  of,  in  soils 

as  operative  and  inoperative,  291,  292 
in  soils  not  distinguished  by  action 

of  alkalies,  295 
in  farm-yard  manure  only  partly 

separable  by  distillation  with  alkalies, 

298 
in   manures   and   soils,   different 

effects  of,  on  what  dependent,  299 
Nitrogenous  food,  experiments  on -the 

growth  of  plants  without,  56 
removed  in  crops  is  more  than  fully 

restored  by  rain,  277 
restored  to  soils  by  fodder  plants, 

310 
Nitrogenous  manures  not    always  the 

most  efficacious,  271 
effects  of,  not  proportional  to  the 

nitrogen  present,  310 

first  effect  of,  312 

when  required,  310 

Nutritive    substances,    closeness   of  in 

soils  (figure),  190 

—  —  proper    relative    proportions   of, 
131 

maximum    and    minimum    of,    in 

soils,  207 

minimum  of,  regulate  the  crop,  207 

effect  of  the  absorption  of,  in  the 

upper  layers  of  the  soil,  152 


Oat,  food  of,  derived  from  arable  soil 
(figure),  200 

—  and  turnip  compared,  53 

—  several  stages  of  growth  of,  49 
Oberbobritzsch,  unmanured  field,  prod- 
uce from,  186 

17 


Oberschona,  unmanured  field,  produce 
from,  186 

Organic  matter  in  manure  does  not  ar- 
rest exhaustion,  182 

incorporation  of  in  soils  improves 

their  physical  condition,  96 

Osmosis,  laws  of,  65 


Palms,  starch  in  stems  of,  335 

Peas  and  barley  plant,  growth  of  com- 
pared, 154 

Perennial  plant,  mode  of  growth  of,  29 

Peruvian  guano,  composition  of,  245 

and  ash  constituents  of  seeds,  dif- 
ference of,  246 

effect  of,  due  to  the  presence  of 

oxalic  acid,  247 

moistened  with  sulphuric  acid  made 

more  quickly  available,  248 

Phosphate  of  lime,  diffusion  of  in  soil,  88 

Phosphoric  acid  and  nitrogen,  proportion 
between  in  oats  and  turnips,  52 

Pierre,  analysis  of  soil  by,  294 

Pincus,  experiments  on  clover  with  gyp- 
sum, 320 

Plants,  annual,  biennial,  and  perennial, 
vital  properties  compared,  29 

—  annual,  mode  of  growth  of,  33 
leafy,  mode  of  growth  of,  43 

—  biennial,  mode  of  growth  of,  34 

—  perennial,  mode  of  growth  of,  31,  41 

—  growth  of,  without  nitrogenous  food, 
56 

—  growth  of  in  turf,  112 

in  solutions  of  their  food,  109 

—  underground  organs  of,  28,  31 

—  rich  in  starch,  sugar,  and  gum,  con- 
tain much  potash  in  their  ash,  39 

—  store  up  food  in  certain  organs  for  fu- 
ture use,  41 

Pools,  analysis  of  stagnant  water  of,  103 
Potash  in  soils,  not  always  available,  238 

—  necessary  for  vegetation,  246 
Potato,  constituents  of,  199 

—  draws  its  principal  constituents  from 
the  arable  surface  soil,  199 

—  effect  of  the  cultivation  of.  on  arable 
soil,  215 

Poudrette,  nature  of,  258 

Practical  men,  236 

their  teaching  and  practice  often 

opposed  to  each  other,  314 

Protoplastem  of  wheat  plants,  propor- 
tion between  nitrogenous  and  non-ni- 
trogenous substances  hi,  54 


11 


Radication  of  plants,  26 

importance  of  a  knowledge  of, 

28 

Rape-cake,  its  composition,  267 
more  diffusible  in  soils  than  guano, 

268 
its  fertilising  action  illustrated  In 

the  Saxon  experiments.  268 


186 


INDEX. 


Rastadt,  soldiers1  food  and  excrements. 

259 
Restoration,  Jaw  of,  properly  interpreted, 

240 
Rhenish  Bavaria,  exhaustion  of  eo.l  of, 

235 

River  waters,  analyses  of,  348 
Roots,  absorption  of  miner:;!  matters  by, 

70,89 

—  absorption  of  food  by,  not  an  osmotic 
process,  65 

—  do  not  offer  permanent  resistance  to 
the  chemical  action  of  salts,  68 

—  importance  of  their  developement  in 
cereals,  48 

—  mode  in  which  they  absorb  food,  106 

—  length  of,  28 

—  power  of  selection  of  food  in,  63,  67 

—  principal  conditions  for  the  formation 
of,  226 

—  spread  in  search  of  food,  93 
Rotation,    succession   of  crops    in,  de- 
pendent on  the  cereals,  227 

—  system  of,  does  not  ultimately  increase 
corn  crops,  232 

—  general  results  obtained  in  the  Saxon 
experiments  by,  270 

Rye,  cultivation  of,  instead  of  wheat, 
shows  deterioration  of  soil,  235, 

—  soil,  120 

conversion  of,  into  wheat  soil,  127 

S 

Sandy  soil,  productive  power  of,  141 

and  loam  compared,  142 

Sap,  Hales'  experiments  on  the  motion 
of,  338 

Saxon  experiments  with  lime,  330 

on  unmatiured  land,  18 

with  farm-yard  manure,  203,  211 

with  bone-earth,  265 

with  rape-cake,  268 

profit  and  loss  of  nitrogen  in  the 

soil,  276 

Schattenmann's  experiments  with  salts 
of  ammonia,  281 

Schmid,  on  nitrogen  In  Russian  black 
soil,  294 

Schonbein,  nitrite  of  ammonia  in  oxida- 
tion and  combustion  discovered  by, 
308 

Sea-salt,  experiments  with,  by  Kuhl- 
mann,  317 

with  cereals,  experiments  by  Ba- 
varian Society,  317 

Seeds,  germination  and  growth  of,  20 

—  conditions  for  the  formation  of,  61 

—  effect  of  mineral  matter  on  the  growth 
of,  57 . 

—  functions  of  nitrogenous  matter  of,  56 

—  importance  of  good,  24 

—  selection  of,  25 

Silicates,  effect  of  organic  matter  in  soils, 

in  the  diffusion  of,  89 
Siliceous  plants,  removed  by  drainage, 

89 
Silicic  acid,  deficiency  or  excess  in  soils 

injurious,  90 


Silicic  acid,  excess  of,  how  remedied, 

90 
distribution  of,  promoted  by  growth 

of  grass-,  89 
Soil  und  subsoil,  75 

—  when  fertile,  75 

—  chemical  analysis  of,  r;o  guide  to  its 
productive  power,  74,  118 

—  exhausted,  how  restored  to  fertility, 
83 

—  estimation  of  substances  physically 
combined  in,  124 

—  for  wheat,  rye,  and  oats,  120, 125 

—  different  layers  of,  contain  food  for 
different  plants,  155 

—  change  produced  by  cereals  in,  218 

—  composition    of,  restored    by  fodder 
plants,  219 

—  distillation  of,  with  alkalies,  296 

—  from  bogs  and  ditches,  fertilising  ef- 
fect of,  105 

—  exhaustion  of,  in  Rhenish   Bavaria, 
235 

—  food  in,  not  inexhaustible,  234,  236 

—  fertility  of,  not  due  to  its   nitrogen, 
289 

—  importance  of  improving  the  physical 
condition  of,  97 

—  mineral  matters  of,  lost  in  corn  and 
cattle  sold,  220 

—  nutritive    power    of,    estimated    by 
amount  of  food  physically  combined, 
82 

—  productive  power  of,  estimated  by  the 
available  nitrogen  in  form  of  ammonia 
and  nitric  acid,  297 

—  progress  of  exhaustion  of,  1G6 

—  production  of  corn  and  straw  in,  dur- 
ing the  progress  of  exhaustion,  170 

—  restoration  of  productive  power  to, 
requires  nitrogenous  as  well  as  miner- 
al food,  309 

—  restoration  of  nitrogenous  food  to,  ef- 
fected by  fodder  plants,  310 

—  permeability  of,  to  manures,  216 

—  productive  power  of,  129 

—  proper  relation  between  food  elements 
in  for  fertility,  130 

—  upper  layers  of,  retain  the  dung  con- 
stituents, 220 

—  saturated  with  mineral  matter,  ma- 
nuring with,  145 

—  absorptive  power  of,  77 
effects    chemical    decomposi- 
tion, 79 

knowledge  of,  valuable,  217 

for  potash,  128 

for  ammonia  increased  by  or 

ganic  matter,  143 
for  phosphates  of  lime    and 

magnesia,  139 

for  silicic  acid,  140 

Starch  in  stems  of  palms,  336 
Stohmann,  experiments  on  the  growth  of 

plants  in  solutions  of  their  food,  356 
Straw,  formation  of,  194, 197 
Subsoi.,  accumulation  of  organic  matter 

in,  injurious  to  deep-rooting  plants,  91 

—  period  of  exhaustion  of,  222 


INDEX. 


387 


SubBoil,  mineral  matter  of,  supplied  to 
surface  soil  by  fodder  plants,  219 

—  not  reached  by  mineral  matters    of 
manures,  156 

Superphosphates,  262 

—  experiments  with,  148 


T 


Tillage,  beneficial  action  of,  118 

Tobacco  plant,  mode  of  growth  of,  43 

quantity  of  albumen  and  nicotine 

in,  modified  by  treatment  in  growth, 
46 

Tscherno-sem,  or  black  earth  of  Russia, 
nitrogen  in,  294 

Turf  saturated  with  food  of  plants,  ex- 
periments with,  112 

Turnips,  growth  of,  34 

influenced  by  removal  of  leaves, 

42 


Unmanured  land,  experiments  in  Saxony 
on, 186 

produce  of,  dependent  on  preced- 
ing crop, 187 


Vfllker,  absorption  of  soils  for  ammonia, 
142 

—  analysis  of  farm  yard  manure.  147 

—  estimation  of  ammonia  in  farm-yard 
manure,  298 


W 

Walnut  leaves,  analysis  of  ash  of,  334 
Water,  drainage,  Jysimeter,  liver   and 
marsh,  analysis  of,  103,  341 

—  in  soils,  contains  different  quantities 
of  nutritive  matters,  105 

Water,  solvent  action   of,  on    soils    in 

Jysimeters,  342  - 

Way,  analysis  of  drainage  water,  341 
Weeds,  cause  of  their  production,  225 
Wheat  crop,  quantity  of  phosphoric  acid 
and  potash  removed  from  soil  by,  as 
compared  with  rye  crop,  123 

—  effect  of  potash  on,  320 

—  field,  retardation  of  the  exhaustion  of, 
173 

—  growth  of,  47,  55 

—  produce  of,  from  salts  of  ammonia, 
according  to  Lawes  and  Gilbert,  304 

—  produce  of,  with  superphosphate  of 
lime,  148 

—  soil,  120 

exhaustion  of,  169 

Winter  wheat,  mode  of  growth  of,  47 

effect  of  temperature  on,  48 

Wood,  ash,  272 

mixed  with  earth  for  application, 

273 

Z 

Zenker,  comparative  experiments  with 

bone-earth  and  guano,  264 
Zinc  in  the  ash  of  Viola  calaminaria,  69 
Zoeller,  experiments  on  the  vegetation  of 

plants  in  turf,  112 

—  mode  of  analysing  soils,  124 

—  analysis  of  guano  by,  246 
lysimeter  waters  by,  342. 


D.  APPLETON  &  CO.'S  PUBLICATIONS. 


THE 

NEW  AMERICAN  CYCLOPEDIA. 

EDITED   BY 

GEORGE  EJPLEY  ANDX  CHARLES  A.  DAM. 

PUBLISHED  BY 

JD.  APPLETON  &  COMPANY,  New  York 
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books.  Its  decision  must  be  final.  It  must  be  an  ultimatum 
of  reference,  or  it  is  good  for  nothing. 

II.  IN  IMPAETIALITY. — Our  work  has  undergone  the  exam- 
ination of  Argus  eyes.    It  has  stood  the  ordeal.    It  is  pro- 
nounced by  distinguished  men  and  leading  reviews  in  all  parts 
of  the  Union,  strictly  fair  and  national.    Eschewing  all  expres- 
sions of  opinion  on  controverted  points  of  science,  philosophy, 
religion,  and  politics,  it  aims  at  an  accurate  representation  of 
facts  and  institutions,  of  the  results  of  physical  research,  of  the 
prominent  events  in  the  history  of  the  world,  of  the  most  sig- 
nificant productions  of  literature  and  art,  and  of  the  celebrated 
individuals  whose  names  have  become  associated  with  the 
conspicuous  phenomena  of  their  age — doing  justice  to  all  men, 
all  creeds,  all  sections. 

III.  IN  COMPLETENESS. — It  treats  of  every  subject,  in  a  terse 
and  condensed  style,  but  fully  and  exhaustively.    It  is  believed 
that  but  few  omissions  will  be  found ;  but  whatever  topics  may, 
through  any  oversight,  be  wanting,  are  supplied  in  an  Appendix. 

IY.  IN  AMEEICAN  CHAEACTEE. — The  New  Cyclopaedia  is 
intended  to  meet  the  intellectual  wants  of  the  American  people. 
It  is  not,  therefore,  modelled  after  European  works  of  a  similar 
design ;  but,  while  it  embraces  all  their  excellences,  has  added 
to  them  a  peculiar  and  unmistakable  American  character.  It 
is  the  production  mainly  of  American  mind. 

Y.  IN  PEACTICAL  BEAEING.— The  day  of  philosophical  ab- 
straction and  speculation  has  passed  away.  This  is  an  age  of 
action.  Cui  lono  is  the  universal  touchstone.  Feeling  this,  we 
have  made  our  Cyclopaedia  thoroughly  practical.  No  man  of 
action,  be  his  sphere  humble  or  exalted,can  afford  to  do  without  it. 


4  D.  APPLETON  &  CO.'S  PUBLICATIONS. 

VI.  IN   INTEEEST  OF  STYLE. — The  cold,  formal,  and  re- 
pulsive style  usual  in  works  of  this  kind,  has  been  replaced  with 
a  style  sparkling  and  emphatically  readable.    It  has  been  the 
aim  to  interest  and  please,  as  well  as  instruct.    Many  of  our 
writers  are  men  who  hold  the  foremost  rank  in  general  litera- 
ture, and  their  articles  have  been  characterized  by  our  best 
critics  as  models  of  elegance,  force,  and  beauty. 

VII.  IN  CONVENIENCE  OP  FOEM. — No  ponderous  quartos, 
crowded  with  fine  type  that  strains  the  eyes  and  wearies  the 
brain,  are  here  presented.     The  volumes  are  just  the  right  size 
to  handle  conveniently ;  the  paper  is  thick  and  white,  the  type 
large,  the  binding  elegant  and  durable. 

VIII.  IN  CHEAPNESS. — Our  Cyclopaedia  has  been  univer- 
sally pronounced  a  miracle  of  cheapness.    We  determined,  at 
the  outset,  to  enlarge  its  sphere  of  usefulness,  and  make  it 
emphatically  a  book  for  the  people,  by  putting  it  at  the  lowest 
possible  price. 

Such  being  the  character  of  the  New  American  Cyclopaedia, 
an  accurate,  fresh,  impartial,  complete,  practical,  interesting, 
convenient,  cheap  Dictionary  of  General  Knowledge,  we  ask, 
who  can  afford  to  do  without* it?  Can  the  merchant,  the 
statesman,  the  lawyer,  the  physician,  the  clergyman,  to  whom 
it  gives  thorough  and  complete  information  on  every  point 
connected  with  their  several  callings?  Can  the  teacher,  who 
is  enabled,  by  the  outside  information  it  affords,  to  make  his 
instructions  doubly  interesting  and  profitable  ?  Can  the  far- 
mer, to  whom  it  offers  the  latest  results  of  agricultural  research 
and  experiment?  Can  the  young  man,  to  whom  it  affords  the 
means  of  storing  his  mind  with  useful  knowledge  bearing  no 
any  vocation  he  may  have  selected?  Can  the  intelligent 
mechanic,  who  wishes  to  understand  what  he  reads  in  his  daily 
paper?  Can  the  mother  of  a  family,  whom  it  initiates  into  the 
mysteries  of  domestic  economy,  and  teaches  a  thousand  things 
which  more  than  saves  its  cost  in  a  single  year?  In  a  word,  can 
any  intelligent  American,  who  desires  to  understand  the  insti- 
tutions of  his  country,  its  past  history  and  present  condition, 
and  his  own  duties  as  a  citizen,  deny  himself  this  great  Ameri- 
can digest  of  all  human  knowledge,  universally  pronounced  the 
best  Cyclopaedia  and  the  most  valuable  work  ever  published? 


THE  NEW  AMERICAN  CYCLOPAEDIA. 


CONTRIBUTORS  TO   THE  CYCLOP/EDIA. 

The  best  talent  in  all  parts  of  the  country,  and  many  dis- 
tinguished foreign  writers,  have  been  engaged  in  the  New 
American  Cyclopaedia.  We  give  below  the  names  of  several  of 
the  most  prominent  contributors,  from  which  the  public  may 
form  some  idea  of  the  character  of  the  work. 


Hon.  GEORGE  BANCROFT,  LL.D.,  New  York. 

Hon.  J.  E.  BARTLETT,  late  U.  S.  and  Mexican  Boundary  Commissioner,  Provi- 
dence, E.  I. 

Eev.  HENRY  W.  BELLOWS,  D.D.,  New  York. 

Hon.  JEREMIAH  S.  BLACK,  U.  S.  Attorney  General,  Washington,  D.  G. 
Capt.  GEORGE  S.  BLAKE,  U.  S.  Naval  Academy,  Annapolis,  Md. 
Hon.  ERASTUS  BROOKS,  New  York. 
EDWARD  BROWN-SEQUARD,  M.D.,  London. 
JOHN  ESTEN  COOKE,  Esq.,  Eichmond,  Va. 

Eev.  J.  W.  CUMMINGS,  D.D.,  Pastor  of  St.  Stephen's  Churah,  New  York. 
Prof.  JAMES  D.  DANA,  LL.D.,  Yale  College,  New  Haven,  Conn. 
Hon.  CHARLES  P.  DALY,  Judge  of  the  Court  of  Common  Pleas,  New  York. 
Hon.  CHARLES  S.  DAVIES,  LL.D.,  Portland,  Me. 
EALPII  WALDO  EMERSON,  Concord,  Mass. 
Hon.  EDWARD  EVERETT,  Boston,  Mass. 
Pres.  C.  C.  FELTON,  LL.D.,  Harvard  University,  Cambridge,  Mass. 

D.  W.  FISKE,  Esq.,  Secretary  of  the  Geographical  and  Statistical  Society,  N^w 

York. 
CHARLES  L.  FLINT,  Esq.,  Secretary  of  the  Massachusetts  Beard  of  Agriculture, 

Boston,  Mass. 

JOHN  W.  FRANCIS,  M.D.,  LL.D. 
Prof.  CHANDLER  E.  OILMAN,  M.D.,  College  of  Physicians  and  Surgeons,  New 

York. 
Prof.  HENRY  GOADBY,  M.D.,  State  Agricultural  College  of  Michigan,  Ann 

Arbor,  Mich. 

HORACE  GREELEY,  Esq.,  New  York. 
GEORGE  W.  GREENE,  Esq.,  New  York. 

E.  A.  GUILD,  Esq.,  Librarian  of  Brown  University,  Providence,  E.  I. 
Prof.  CHARLES  W.  HACKLEY,  D.D.,  Columbia  College,  New  York. 
Hon.  JAMES  HALL,  Cincinnati,  Ohio. 

GERARD  HALLOCK,  Esq.,  editor  of  the  "  Journal  of  Commerce,"  New  York. 

Prof.  A.  W.  HARKNESS,  Brown  University,  Providence,  E.  I. 

JOHN  E.  G.  HASSARD,  Esq.,  New  York. 

CHARLES  C.  HAZEWELL,  Esq.,  Boston,  Mass. 

M.  HEILPRIN,  Esq.,  New  York. 

EICHARD  HILDRETH,  Esq.,  author  of  "  History  of  the  United  States,"  Ac.,  New 

York. 

Eev.  THOMAS  HILL,  President  of  Antioch  College,  Ohio. 
Hon.  GEORGE  S.  HILLARD,  Boston,  Mas*. 


D.  APPLETON  &  CO.'S  PUBLICATIONS. 


CONTRIBUTORS    TO    THE    CYCLOP/EDIA. 

J.  S.  HITTELL,  Esq.,  San  Francisco,  Cal. 

JAMES  T.  HODGE,  Esq.,  Cooper  Institute,  New  York. 

Prof.  L.  M.  HUBBARD,  D.D.,  University  of  N.  C.,  Chapel  Hill,  N.  C. 

Kev.  HENEY  N.  HUDSON,  author  of  "  Lectures  on  Shakespeare,"  &c.,  Litch« 

field,  Conn. 

Prof.  S.  W.  JOHKSON,  Tale  College,  New  Haven,  Conn. 
J.  C.  G.  KENNEDY,  Esq.,  "Washington,  D.  C. 

Hon.  JOHN  B.  KERR,  late  U.  S.  Minister  to  Central  America,  Baltimore,  Md. 
Eev.  T.  STARR  KING,  San  Francisco,  Cal. 
CHARLES  LANMAN,  Esq.,  "Washington,  D.  C. 
CHARLES  G.  LELAND,  Esq.,  Philadelphia,  Pa. 
Prof.  JAMES  E.  LOWELL,  Harvard  University,  Cambridge,  Mass. 
E.  SIIELTON  MACKENZIE,  D.C.L.,  Philadelphia,  Pa. 

Eev.  II.  N.  MCTYEIRE,  D.D.,  editor  "  Christian  Advocate,"  Nashville,  Tenn. 
.CHARLES  NORDIIOFF,  Esq.,  author  of  "Stories  of  the   Island  World,"  &c,  New 

York. 

Eev.  SAMUEL  OSGOOD,  D.D.,  New  York. 

Prof.  THEOPIIII.US  PARSONS,  LL.D.,  Harvard  University,  Cambridge,  Mass. 
Prof.  E.  E.  PEASLEK,  M.D.,  New  York  Medical  College,  New  York. 
JOHN  L.  PEYTON,  Esq.,  Staunton,  Ya. 

WILLIAM  C.  PRIME,  author  of  "  Boat  Life  and  Tent  Life,"  &c.,  New  York. 
J.  II.  EAYMOND,  LL.D.,  Principal  of  the  Polytechnic  Institute,  Brooklyn,  New 

York.' 
GEORGE  SCIIEDEL,  Esq.,  late  British   Consular  Agent  for  Costa  Eica,  Staten 

Island,  N.  Y. 

Prof.  ALEXANDER  G.  SCHEM,  Dickinson  College,  Carlisle,  Peiin. 
Hon.  FRANCIS  SCIIROEDEK,  JR.,  late  U.  S.  Minister  to  Sweden,  Paris. 
Hon.  WILLIAM  II.  SEWAKD,  U.  S.  Senator  from  New  York,  Auburn,  N.  Y. 
WILLIAM  GILMOKE  SIMMS,  LL  D.,  Charleston,  S.  C. 
Prof.  HENRY  B.  SMITH,  D.D.,  Union  Theological  Seminarv,  New  York. 
Eev.  J.  A.  SPENCF.I:,  D.D.,  author  of  "The  History  of  the  United  States,"  &c., 

New  York. 

Rev.  WILLIAM  B.  SPUAGUE,  D.D.,  Albany,  N.  Y. 
Hon.  E  G.  SQITIEK,  author  of  "  The  States  of  Central  America,"  "  Nicaragua,'1 

&c. 

ALEX.  W.  TIIAYEK,  Esq.,  Berlin,  Prussia. 
JOHN  E,  THOMPSON,  Esq.,  editor  "  Southern  Literary  Messenger,"  Eichrnond, 

Ya. 

GEORGE  TICKNOR,  LL.D.,  Boston,  Mass. 
OSMOND  TIFFANY,  Esq.,  Springfield,  Mass. 

E.  T.  TBALL,  M.D.,  author  of  "Hydropathic  Encyclopaedia,"  New  York. 
Baron  DE  TROBRIAND,  New  York. 

W.  P.  TP.OWBRIDGE,  Esq.,  U.  S.  Coast  Survey,  Washington,  D.  C. 
HENRY  T.  TUCKERMAN,  Esq.,  New  York. 

ALEXANDER  WALKER,  Esq.,  editor  of  the  "  Delta,"  New  Orleans. 
CHARLES  S.  WEYMAN,  Esq.,  New  York. 

Eev.  W.  D.  WILSON,  D.D.,  Hobart  Free  College,  Geneva,  N.  Y. 
£.  L.  YOXTMANS,  Esq.,  author  of  "  The  Hand-Book  of  Household  Science," 

'  New  York. 


THE  NEW  AMERICAN  CYCLOPAEDIA. 


OPINIONS  OF  THE  PRESS  AND  DISTINGUISHED  MEN. 

In  setting  forth  what  the  Press  think  of  the  New  American 
Cyclopaedia,  we  hardly  know  where  to  begin,  so  numerous  and 
flattering  are  the  notices  it  has  received.  "We  can  only  give 
here  and  there  a  hrief  extract  from  the  leading  Reviews  and 
Journals,  and  letters  from  distinguished  men,  bearing  for  the 
most  part  on  special  features  of  the  work. 

The  work  itself  no  longer  needs  commendation  at  our  hands,  or  at  any  hands.  It 
has  long  since  established  its  worth;  and,  if  there  be  in  it  any  considerable 
defect,  tnuch  search  will  be  required  to  find  it. — North  American,  Philadel- 
phia, Pa. 

The  great  arts  of  condensation,  of  clear  perception,  and  striking  exposition  of  the 
essential  parts  of  their  subject  have  been  fully  attained;  and  will  give  the 
reader  a  library  of  universal  knowledge  in  a  convenient  compass,  arranged  for 
ready  use,  and  attractively  presented  in  the  concise  and  perspicuous  style  ap- 
propriate to  such  a  work. — Letter  from  the  late  Hon.  Tnos.  H.  BENTON. 

This  work,  instead  of  being  a  mere  dictionary — a  stupid  epitome  of  dry  facts  and 
dates— is  made  up  of  attractive  and  readable  matter;  scholarly  and  sparkling 
essays;  fresh  biographies  of  living  and  dead  celebrities;  records  of  important 
discoveries  and  inventions;  and  information  on  every  subject  that  has  attract- 
ed the  attention  of  man  up  to  the  present  period.— Examiner,  Poughkeepsie, 
N.  Y. 

I  feel  quite  sure  that  it  will  be  marked  by  distinguished  ability,  and  that,  when 
concluded,  it  will  be  a  vast  storehouse  of  late  and  very  important  information 
— such  a  work  as  almost  every  intelligent  person  will  be  glad  to  have  always 
near  him  for  reference.  I  can  only  express  the  hope  that  so  large  an  under- 
taking may  be  duly  sustained,  and  crowned  with  ultimate  success.— Letter 
from  the  Rt.  Rev.  HORATIO  POTTER,  (Prot.  Epis.~)  Bishop  of  N.  Y. 

The  editors  have  done  their  duty  with  justice,  fairness,  and  liberality.  We  see 
no  instance  of  partisanship  or  partiality,  and,  as  yet,  no  proofs  of  that  hostile 
sectionality  of  which  we  have  hitherto  had  reason,  in  all  such  publications,  to 
complain. — Mercury,  Charleston,  S.  C. 

We  esteem  it  the  best  and  most  comprehensive  Cyclopedia  that  has  yet  been  is- 
sued  from  the  press  of  this  or  any  other  country.— News,  Savannah,  Ga. 

When  completed,  this  Cyclopaedia  will  be  the  most  complete  library  of  knowledge 
which  has  ever  been  given  to  the  world  in  the  same  space  since  the  art  of 
printing  was  discovered.—  Union,  Rochester,  N.  Y. 

Its  freshness  and  general  thoroughness  give  it  a  decided  advantase  over  any 
other  Cyclopaedia  of  its  class  hitherto  issued  on  either  side  of  the  Atlantic  — 
Daily  Times,  N.  Y. 

It  is  a  perfect  treasury  of  knowledge.  In  all  branches  of  the  arts  and  sciences,  i« 
literature,  history,  biography,  and  geography.—  Pilot,  Boston,  Mass. 


D.  APPLETON  &  CO.'S  PUBLICATIONS. 


OPINIONS   OF  THE  PEESS. 

The  scientific  articles  are  evidently  the  productions  of  learned  and  accomplished 
men.  Many  of  the  papers  deserve  especial  commendation,  as  presenting  the 
latest  developments  in  their  various  departments  of  research. — National  In- 
telligencer, Washington,  D.  C. 

Our  own  country  has  never  before  been  so  fairly  or  fully  represented  in  any  Cy- 
clopaedia. America,  her  resources,  her  literature,  her  politic?,  and  her  repre- 
sentative men  receive  in  this  work,  at  least,  their  full  share  of  attention.— 
Post,  Boston,  Mass. 

To  enumerate  one  half  of  its  excellences  would  require  far  more  space  than  news- 
paper columns  afford.  To  the  professional  man  and  the  laborer,  the  citizen 
and  the  farmer,  it  is  invaluable  as  an  epitome  of  all  useful  knowledge. — Lead- 
er, Cleveland,  O. 

There  is  no  conceivable  topic  which  is  not  here  discussed  as  fnlly  as  most  persons 
would  care  to  find  it. — American  Agriculturist. 

It  should  be  in  every  family,  for  in  no  other  shape  can  so  much  useful  information 
be  obtained  as  cheaply.  As  a  book  of  reference,  it  is  invaluable. — Indiana 
Sentinel. 

It  is,  without  doubt,  the  most  complete  work  of  the  kind  ever  published.  To 
prepare  it,  the  publishers  have  called  into  requisition  the  talent  of  some  of  the 
best  men  our  country  affords. — Pennsylvanian,  Philadelphia,  Pa. 

There  can  be  no  doubt  that,  at  least  for  the  use  of  American  readers,  and  in  some 
respects  wherever  the  English  language  is  spoken,  the  Cyclopaedia  will 
GREATLY  SURPASS,  in  its  value  as  a  reference  book,  any  similar  compilation 
that  has  yet  been  issued  on  either  side  of  the  Atlantic. — North  American 
Review. 

Take  it  all  in  all— for  the  strict  purposes  of  an  Encyclopaedia;  for  a  clear  survey  of 
all  the  departments  of  human  knowledge ;  for  embracing  every  important 
topic  in  this  vast  range;  for  lucid  and  orderly  treatment;  for  statements  con- 
densed yet  clear;  for  its  portable  size— not  being  too  large  or  too  small ;  for 
convenience  of  reference,  and  for  practical  utility,  especially  to  American 
readers;  it  is  incomparably  the  best  work  in  the  English  language.— N. 
Y.  Evangelist. 

It  is  a  most  extraordinary  effort  of  genial  scholarship  and  of  multurn  inparvo 
erudition.  We  commend  it  as  a  book  which  the  world  h»  long  wanted,  and 
which  will  exert  an  incalculable  influence  in  Europe  as  regards  creating  re- 
spect  for  solid  American  learning.-  Telegraph,  Hamburgh,  Pa, 

It  has  been  truly  said  that  almost  every  man  of  note  who  ever  lived  and  died,  of 
whom  there  is  record,  has  in  it  a  place;  every  country,  province  race  and 
tribe ;  every  sea,  river,  lake  and  island ;  every  science,  religion,  and,  in  short, 
almost  every  noun  in  tho  language,  is  descriptively  illustrated  in  the  most 
complete  shape  in  winch  the  information  could  be  condensed.— L  M*  ^ 
do,  0. 

The  various  subjects  are  not  treated  according  to  the  mere  routine  of  technical 
details,  or  in  the  settled  formularies  of  professional  science,  but,  while  the  i: 
formation  is  full,  thorough,  and  accurate,  it  is  given  in  a  genial  and  attractive 
style.— -Tribune,  Mobile,  Ala. 


14  DAY  USE 

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